Spicule Sheath Research Articles

Phylogenetic evidence of a possible Trichuris globulosa species complex in Arabian camels from Kuwait.

During a 1-year study, Trichuris adults were obtained after necropsy of Arabian camels (Camelus dromedarius) from a slaughterhouse in Kuwait. Morphological and molecular identification was performed to confirm the identity of the Trichuris specimens obtained from C. dromedarius. Fifteen male Trichuris specimens were selected, and molecular identification was performed using mitochondrial cytochrome c oxidase subunit I, 12S ribosomal RNA, 16S ribosomal RNA genes and the nuclear internal transcribed spacer 2 (ITS2) region. Through phylogenetic analysis, 2 distinct groups were obtained using the mitochondrial genes, where group 1 showed a close relationship to Trichuris globulosa while group 2 showed a close relationship to Trichuris ovis, providing molecular evidence of a possible T. globulosa species complex. Additionally, the nuclear ITS2 region did not provide enough resolution to distinguish between the 2 groups of Trichuris specimens. Observation of morphological characters revealed variations in the shape of the male spicule sheath, where specimens present either a globular posteriorly truncated swelling or the absence of posteriorly truncated swelling. Moreover, the variations in male spicule sheath does not corroborate with the results of molecular data, suggesting the limited use of this character for identification of T. globulosa. In conclusion, molecular analysis suggests a possible species complex in T. globulosa, with the mitochondrial genetic markers successfully differentiating between the 2 groups. The limited use of the male spicule sheath as a diagnostic character for identification of T. globulosa is suggested.

A new record of the occurrence of Trichuris skrjabini Baskakov, 1924 in goats of Pakistan.

More than 23 Trichuroidea species have been identified in ruminants in different parts of the world. Most are pathogenic, causing trichurosis. Trichuris adults of most species within this family have a predilection for the ceca, where they may cause damage to the epithelial wall. In the present study, Trichuris spp. from large intestine of goats were analysed based on morphological and molecular characteristics. Fifty adult worms (male = 25 and female = 25) were selected for morphometric and molecular analysis. Male Trichuris were distinguished by their longer spicules, typical spicule sheaths, and small spicules that were always completely covered by the spicule sheath. The presence of an uneverted vulva in the vagina distinguished female worms. We have performed the molecular characterisation of adult warms to identify as Trichuris skrjabini. Genetic comparison of T. skrjabini rDNA ITS2 sequences with those from other Trichuris spp. was performed to assess within and between species variation and validate the use of ITS-2 rDNA as a robust species-specific marker for T. skrjabini identification. This work provides the first report of this parasite species from Pakistan and validated species-specific marker of T. skrjabini that reduces the production potential of goats in the country.

Morphological Characteristics of Parasitic Nematodes Trichuris sylvilagi (Nematoda, Trichuridae)

Morphometric parameters are analyzed and systematized of parasitic nematodes of the species Trichuris sylvilagi Tiner, 1950, obtained from Lepus europaeus (Pallas, 1778). The following parameters are suggested for the exact identification of female T. sylvilagi nematodes: the sizes of body, its anterior and posterior parts, width of body at the connection of esophagus and intestine, specific location of vesicular cuticular protrusions and vulva. Five metric parameters are established for the nematode eggs. The egg shell thickness, length and width of egg plug are suggested for use in addition to the length and width of eggs. Males of T. sylvilagi had strongly curved tail end, long spicule, and transparent spicule sheath which bears spines, and a bulbous inflation in its proximal part. The thirteen metric parameters, which we found to be of identification value for males, include sizes of body, length and width of its anterior and posterior parts, width of body at the connection of esophagus and intestine, sizes of spicule at various areas, and location of the vesicular cuticular protrusions. Obtained data on the metric studies of T. sylvilagi nematodes are compared with the published data.

Morphometric Analysis of Сapillaria anatis (Nematoda, Capillariidae) from Anas platyrhynchos domesticus

The study presents species-specific morphological traits and metric parameters of mature male and female Сapillaria anatis (Nematoda, Capillariidae) nematodes. The capillariids were obtained by examinations of caeca of 205 domestic ducks (Anas platyrhynchos dom.), reared at poultry farms of Poltava, Sumy and Kyiv Regions of Ukraine. Noted sexual dimorphism was significant by seven morphometric parameters, with measurements of females being larger by 12.40–29.69 % than those of males. In addition to species-specific traits, other diagnostic characters were proposed in male and female С. anatis. In males, such taxonomically important features are morphological specifics of pseudobursa, spicule and ornamentation of spicule sheath. In identification of females, morphology of the vulvar area and eggs in uterus should be considered. Eleven metric parameters are suggested for better differential diagnostics of С. anatis.

Morphobiological analysis of Trichuris vulpis (Nematoda, Trichuridae), obtained from domestic dogs

The parasitic nematode Trichuris vulpis Frölich, 1789 is the pathogen of trichuriasis in domestic and wild carnivores, and humans. This helminth species is distributed world-wide in populations of domestic dog (Canis lupus familiaris). The prevalence of T. vulpis in dogs depends to a large degree on the morphofunctional and biological adaptations of the parasite which support its high survivability in various environmental conditions. The present study considers the species-specific peculiarities of morphology, and metric parameters of the mature and embryonic stages of Trichuris nematodes parasitizing in C. lupus familiaris. We studied the periods of stages of development and infectious egg formation, and their survivability under optimal conditions for T. vulpis in laboratory culture. The differential characteristics of both female and male adult T. vulpis nematodes include the metric characteristics of cuticular protrusions at the surface of the anterior body part. The male T. vulpis nematodes can be distinguished from males of other species by the specifics of spicule sheath ornamentation, the shape and size of spicule, and the width of spicule sheath at different sections. In identification of the female nematodes of this species, it is necessary to consider the presence and size of papillary processes in the vulval area and metric parameters of vulva location. Nine metric characters of sexual dimorphism are described for T. vulpis nematodes. In laboratory conditions, five embryonic stages were observed for T. vulpis: protoplast, blastomere cleavage, and formation of bean-like embryo, larva and mobile larva. These stages are characterized by specific morphological features. The egg develops to the infectious stage at 27 °С in 18 days of culture, and their survivability is up to 76.6%. The egg development is associated with changes in their metric characters, such as decreasing egg length and width of egg shell, and increasing egg width and egg plug width.

Differential species characters of Baruscapillaria anseris and B. obsignata nematodes obtained from the domestic goose

The study presents species composition and abundance of nematodes of the family Capillariidae (Nematoda, Trichocephalida), parasitizing the domestic goose (Anser anser dom. Linnaeus, 1758) in Poltava region, Ukraine. Morphological specifics of adult specimens of collected helminths are examined and new data is obtained for species identification of Capillariidae considering their metric parameters. The pathogens of capillariasis in geese are represented by two species, Baruscapillaria anseris (Madsen, 1945) Moravec, 1982 and B. obsignata (Madsen, 1945) Moravec, 1982 with the former predominant. Prevalence of infection by B. anseris in domestic fowl was up to 46.8%, the abundance index reached 17.9 specimens. The proportion of geese infected with B. obsignata was 23.9%, and the abundance index was 3.8 specimens. Morphological study of the collected mature male and female nematodes revealed the significant similarity of both species in the general body structure and in identification characters: vulva and vagina structure in females, tail end, spicule and spicule sheath in males. Statistically significant differences were determined in the metric parameters of male and female B. anseris and B. obsignata nematodes. Those differences can be used to improve species identification. Males of B. anseris were larger than males of B. obsignata by 16 metric parameters including the length and width of body, spicule and spicule sheath, width of pseudobursa, and distance between the rays of pseudobursa. Females of B. anseris and B. obsignata were significantly different by seven metric parameters. By five parameters (length and width of various body regions) the B. anseris females were larger than B. obsignata. Metric parameters of the studied species are also of interest for taxonomic identification: the eggs of B. obsignata are longer and narrower than those of B. anseris.

Species-specific morphological characteristics of adult and embryonic Capillariа obsignata roundworms (Nematoda, Capillariidae)

The abundance of Capillaria obsignata Madsen, 1945, the causative agent of chicken capillariasis, was studied in the central region of Ukraine. Differential morphometric characters are determined for adult males and females of C. obsignata. The species-specific variability of its morphological parameters is characterized. New data is received on the meristic characters of C. obsignata eggs extracted from different substrates. The stages of embryonic development are determined in laboratory cultures of these nematodes, taking into account their meristic and morphological changes. Capillaria obsignata parasites are very common at the poultry farms of Poltava and Kyiv regions of Ukraine. Their abundance index is 3.4, and the intensity of infection varies from 3 to 317 specimens. Differential morphometric species-specific characters of adult C. obsignata males are the shape and size of the pseudobursa, spicule, spicule sheath. Adult females of the species can be identified by the shape and size of the vulva, the distance from the esophagus end to the vulva, and the length of the vagina. The meristic characters of nematode eggs, though typical for the species, may change depending on the sampled substrate. The parasite’s embryonic development involves five morphologically and meristically different stages. The invasive larvae of this species developed in the eggs before the 12th day of culturing in laboratory conditions at 25 °С. The invasive larvae’s viability was 90.3 ± 1.5%.

Capillaria appendigera n. sp. (Nematoda: Capillariidae) from the goldbanded jobfish Pristipomoides multidens (Day) (Lutjanidae) and new records of other intestinal capillariids from marine perciform fishes off Australia.

Based on light and scanning electron microscopical studies, a new nematode parasite, Capillaria appendigera n. sp. (Capillariidae), is described from the intestine of the goldbanded jobfish Pristipomoides multidens (Day) (Perciformes, Lutjanidae) from the Arafura Sea West, off the northern coast of Australia. The new species, belonging to the subgenus Procapillaria Moravec, 1987, differs from other congeneric species from fishes mainly in the length (0.92-1.13mm), shape and structure of the spicule, obtuse spines on the spicule sheath and the structure of eggs. It is characterised, in the male, by the presence of two well-developed dorsolateral caudal lobes, a pair of lateral papillae, a heavily sclerotised spicule with many rough transverse grooves covering almost the entice spicule surface (except for spicule ends), a spinose spicule sheath, and in the female, by a subterminal anus, mostly the presence of a large vulval appendage and by eggs (size 54-69×27-33µm) encapsulated by a conspicuous light-coloured superficial layer. Capillaria appendigera n. sp. is the 12th nominal species of capillariids recorded from fishes in Australian waters and the second known capillariid species parasitising fishes of the perciform family Lutjanidae. In addition, four unidentifiable, morphologically different types of capillariid females, probably representing undescribed species, were recorded from the intestines of marine fishes off the northern coast of Australia: Capillariidae gen. sp. 1 and Capillariidae gen. sp. 2 from Lutjanus johnii (Bloch) and L. malabaricus (Bloch & Schneider), respectively (both Lutjanidae), Capillariidae gen. sp. 3 from Protonibea diacanthus (Lacépède) (Sciaenidae) and Capillariidae gen. sp. 4 from Rachycentron canadum (Linnaeus) (Rachycentridae).

Description of a new species, Trichuris ursinus n. sp. (Nematoda: Trichuridae) from Papio ursinus Keer, 1792 from South Africa

In the present work, we carried out a morphological, biometrical and molecular study of whipworms Trichuris Roederer, 1761 (Nematoda: Trichuridae) parasitizing Papio ursinus Keer 1792 (Chacma baboon). Biometrical and molecular data suggest a new species of Trichuris parasitizing baboons. In addition of main morphological features (spicule, spicule sheath, spicule tube, proximal cloacal tube, distal cloacal tube, vulva, vagina), the mean values of individual variables between Trichuris colobae, Trichuris suis, Trichuris trichiura examined by Student's t tests suggest that T. ursinus n. sp. constitutes a new species. The combined analysis of three markers (cox1, cob and ITS2) revealed a sister relationships between T. colobae and T. ursinus n. sp. Mitochondrial sequences revealed a higher inter-specific similarity between T. ursinus n. sp., T. suis and T. colobae. Phylogenetic hypotheses for both mitochondrial genes strongly supported distinct genetic lineages corresponding to different species of the genus Trichuris associated with certain hosts. Thus, T. suis, T. colobae and T. ursinus n. sp. appeared as a sister group and separated from Trichuris spp. from humans and other species of primates.

Ultrastructure of Capillaria hepatica (Syn. Calodium hepatica) Isolated from the Liver of Mouse Infected with Artificially Embryonated Eggs Collected from House Rats (Rattus norvegicus)

Capillaria hepatica (syn. Calodium hepatica) is a parasite found mainly in rodent liver. But, it has also been found in a wide variety of mammals, including humans. This worm is unique as it is the only nematode parasite that is embedded in the liver parenchyma of the host even during the adult stage of the life cycle. They produce eggs that elicit a marked granulomatous reaction that eventually destroys the worms. Fibrosis and lymphoplasmacytic inflammatory infiltration are often observed around adult nematodes embedded in the liver parenchyma of the host. For this reason, complete isolation of this slender worm and observation of the intact ultrastructure is very difficult. In this study, 10 intact whole worms (C. hepatica) were isolated from the liver of 3-week-old mouse after inoculation of artificially embryonated eggs collected from house rats (Rattus norvegicus). Their external structure of was observed with light and scanning electron microscopy. The length of the isolated female and male C. hepatica was approximately 69.60 mm and 36.92 mm, respectively. More detailed ultrastructure, including bacillary band, eggs and vulva in female and spicule and spicule sheath in male C. hepatica was also described.

Structure and function of the male copulatory apparatus of the nematodes Capillaria hepatica and Trichuris muris.

The anatomy of the terminal male reproductive system was studied by light microscopy and by scanning and transmission electron microscopy. In C. hepatica a common muscle sphincter surrounds the vas deferens and intestine at their point of juncture. The cloaca is divisible into proximal and distal portions. The spicule is formed in a short ventral spicule pouch but lies mainly in the distal cloaca. The spicule is retracted in C. hepatica by a paired retractor muscle and in T. muris by a single retractor muscle. Protraction of the spicule occurs by contraction of longitudinal muscles surrounding the distal cloaca. This results in the surface layers of the cloacal cuticle being everted as the spicule sheath. The spicule is tubular with a cellular core including multiple sensory receptors at its tip. The spicule is probably solely a chemosensory organ. Mechanical stimulation in the region of the distal cloaca resulted in activation of the spicule and spicule sheath. Response to mechanical stimulus is age dependent.

The ultrastructure of the cuticle of the nematode Syphacia obvelata (Rudolphi, 1802). III. Cuticle associated with the male reproductive structures

Mamelons of male Syphacia obvelata are ventrally situated copulatory structures bounded by cuticle, and internally composed of muscles. Extracuticular spines are found at the apex of each annulus making up the mamelon. The cloaca is formed by an invagination of body wall cuticle, as is the spicule sheath (a portion of the cloacal wall surrounding the free end of the spicule). The spicule, accessory piece, and papillae are innervated and probably function as mechanoreceptors facilitating the positioning of the cloacal region over the vulva during copulation. Dense material forming the gubernaculum, spicule, and accessory piece is distinct from the body wall cuticle. The cortex and basal zones are apposed around the cloacal opening and probably strengthen this area. On the other hand, cuticle lining the cloaca is composed of cortex and an expanded inner zone of matrix material. This matrix material would allow considerable modification in the shape of the cloacal wall during copulation. The apposition of cortex and basal zones over the tip of anal papillae would ensure effective transmission of pressures to the nerve process.

Anatrichosoma buccalis sp. n. (Nematoda: Trichosomoididae) from the Buccal Mucosa of the Common Opossum, Didelphis marsupialis L.

The worm is described from the mucosa of the hard palate, gums, and tongue of the common opossum, Didelphis marsupialis, from Louisiana, Costa Rica, and Colombia. The new species differs from other described species of the genus by its marsupial host, the unique location in the host, and certain morphological characters. The pathology and certain observations on the biology of this species are discussed. This is the first report of this genus from a host indigenous to the Western Hemisphere. Anatrichosoma gerbillis Bernard comb. n. is proposed for Trichosomoides gerbillis Bernard, 1964. Nematodes of the genus Anatrichosoma were recovered from the buccal mucosa of the common opossum, Didelphis marsupialis, from southern Louisiana, Costa Rica, and Colombia. The host and unique location of these parasites together with certain morphological characters provide the basis for the description of a new species of the genus Anatrichosoma. Nematodes were fixed in glacial acetic acid, stored in a mixture of 95 parts 70% ethyl alcohol and 5 parts glycerin, and studied in glycerin mounts after evaporation of the alcohol. In the following description all measurements are in millimeters unless otherwise indicated. The range of measurements and their means of the paratypes follow in parentheses the values for the holotype and allotype. Drawings were made with the aid of a camera lucida. Anatrichosoma buccalis sp. n. (Figs. 1-7) Description: Trichuroidea Railliet, 1916, Trichosomoididae York and Maplestone, 1926, Anatrichosomatinae Smith and Chitwood, 1954, Anatrichosoma Smith and Chitwood, 1954. With the characters of the genus. Small, slender nematodes. Received for publication 17 March 1972. * Supported in part by the Tulane University International Center for Medical Research and Training grant AI-10050 from the NIAID, NIH, U. S. Public Health Service. t Department of Tropical Medicine and Medical Parasitology, Louisiana State University Medical Center, New Orleans, Louisiana 70112. t Department of Tropical Medicine and Parasitology, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112. Body of female increasing in diameter from anterior to posterior. Body of male uniform in diameter throughout most of length, slightly tapered at anterior and posterior extremities, diameter less than one-third that of female, length same as female or slightly longer. Cuticle thick, transparent, with two broad lateral bacillary bands extending entire length of body. Head with two lateral amphids, cephalic papillae absent or inapparent. Lips absent, oral opening dorsoventrally elongate, small stylet present. Cephalic inflation present in female, absent in male. Cuticle of female greatly thickened from just posterior to cephalic inflation to near end of second stichocyte. Nerve ring just posterior to cephalic inflation in female. Preglandular esophagus elongate, muscular. Anterior stichocytes longer than wide, gradually becoming larger, more compacted, and wider toward posterior extremity of esophagus. Intestine terminating in a small muscular rectum. Anus terminal. Vulva at level of or just posterior to last stichocyte, lips salient. Cloaca of male terminal, without spicule or spicule sheath. Posterior extremity of male with 2 small lateral papillae. Egg bipolar, thick-walled, with well-developed larva when laid. Female (based on holotype and 41 paratypes): 25.1 (17.3 to 34.0, 25.5) long, 215 (110 to 280, 192) pu in maximum width. Anterior region of body (anterior extremity to esophagointestinal junction) 3.6 (2.8 to 4.9, 3.7) long, 140 (85 to 165, 137) p wide at last stichocyte, muscular portion of esophagus 230 (150 to 265, 235) IA long, nerve ring 63 (55 to 67, 62) uf from anterior extremity, stichocytes 92 (71 to 93, 84) in number. Posterior region of body 21.5 (14.5 to 29.6, 21.7) long. Ratio of anterior body region to total length 1:7.0 (1:5.8 to 1:8.3, 1:6.9). Eggs 61 (53 to 70, 62) i long, 37 (32 to 40, 35) u wide. Male (based on allotype and 10 paratypes): 28.3 (22.0 to 29.0, 27.6) long, 55 (45 to 55, 50) )u maximum width. Anterior region of body 5.1 (3.6 to 5.2, 4.6) long, 45 (45 to 54, 49) u wide at last stichocyte, muscular portion of esophagus 220 (210 to 280, 226) /u long, nerve ring 64 (60 to 67, 64) u from anterior extremity, stichocytes 81 (74 to 86,

Nematode parasites of Oceanica

Viktorocara acholonui sp.nov. is described from a babbler, Alcippe brunnea, from Taiwan. It differs from V. charadrii Belopolskaja, 1959, and V. guschanscoi Leonov, 1958, in having a longer pharynx and in shape of tip of left spicule, and from V. tenuis (Maplestone, 1932) in having 6 rather than 10–13 pairs of preanal papillae.Smetaleksenema gen.nov. is proposed for Skrjabinobronema pileati Smetanina et Alekseev, 1968, which becomes Smetaleksenema pileati (Smetanina et Alekseev, 1968), comb.nov. It differs from Ancyracanthopsis Diesing, 1861, in having serrated cephalic processes. The species is redescribed.Ornithostrongylus vetterlingi sp.nov. is described from emerald doves, Chalcophaps indica, from Borneo and Palawan. It differs from all other species in the shape of the gubernaculum and in possessing a striated, common spicule sheath which binds the spicules tightly together.Also reported and briefly discussed are: Viguiera dicrurusi Gupta, 1960; V. buckleyi (Yeh, 1954) Chabaud, 1957; Cyrnea (P.) excisiformis Yamaguti, 1935; C. (P.) leptoptera (Rudolphi, 1819) Chabaud, 1958; C. (C.) eurycerca Seurat, 1914; Physaloptera alata Rudolphi, 1819; Ornithostrongylus quadriradiatus (Stevenson, 1904) Travassos, 1914; O. travassosi Maplestone, 1932; Amidostomum skrjabini Boulenger, 1926; and Epomidiostomum anatinum Skrjabin, 1915.We wish to acknowledge the field support by Dr D. S. Rabor, Department of Biology, Silliman University, Dumaguete City, Negros Oriental, Republic of the Philippines, and the technicians of the Parasitology Department of Naval Medical Research Unit No. 2 for general assistance in procurement and examination of hosts, and to Mr H. G. Deignan (deceased), U.S. National Museum, for identification of birds.Initial work for this study was supported by funding under Public Law 480, section 104(c), by funds provided by the Bureau of Medicine and Surgery, Navy Department Work Unit MR 005.20-0098, by contract no. NR 103-690/N 0014-66-C0094, between the Office of Naval Research, Department of the Navy, and the Southwest Foundation for Research and Education, and research grant HE-5-P01-6M-13252-02 from National Institutes of Health, USPHS.Final efforts were sponsored by Department of the Army, contract no. DADA17-68-C-8094.

Capillaria colubra sp. n. from the Oviducts of Coluber constrictor priapus

Capillaria colubra sp. n. is described from the oviducts of the southern black racer, Coluber constrictor priapus, from southern Louisiana. It is distinguished from the closely related Capillaria heterodontis by its larger size, transverse striations on the spicule and spicule sheath, and a more elaborate caudal bursalike expansion and two ventral papillae in the male. It is smaller and has a lower ratio of anterior to posterior body regions than Capillaria longispicula. It differs from other snake capillarids in its greater size, higher ratio of anterior to posterior body regions, larger eggs, and more elaborate male caudal bursalike expansion. This is the first capillarid reported from the oviducts of a vertebrate host. Several species of Capillaria have been reported from snakes in South and Middle America (Teixiera de Freitas and Lent, 1935; Aravjo and Gandra, 1943; Caballero and Cerecero, 1944; Yamaguti, 1961). However, Capillaria heterodontis Harwood, 1932, is apparently the only species described from a snake endemic to the United States. Between 1967 and 1969 17 specimens of Capillaria were removed from the oviducts of three southern black racers collected near New Orleans, Louisiana. These specimens represent a new species. Capillarids were removed from the oviducts, fixed in glacial acetic acid, stored in a mixture of alcohol, formalin, and glycerin, and studied in glycerin mounts after evaporation of the alcohol at room temperature. Drawings were made with the aid of a camera lucida. In the following description measurements are in millimeters unless otherwise noted. Capillaria colubra sp. n. (Figs. 1-6) Definition: Trichuridae Railliet, 1915; Capillariinae Railliet, 1915; Capillaria Zeder, 1800. Body diameter increasing from anterior to about the posterior three-fourths. Body very slender, threadlike. Cuticle smooth. Two lateral bacillary bands. Mouth small, porelike. Esophagus consisting of a single chain of stichocytes, some cells darker than others and containing granules, alternating with lighter cells devoid of granules. Anterior region shorter than posterior region of body in male and female. Female slightly longer than male. Received for publication 10 October 1969. * Supported in part by a Predoctoral Fellowship, 5-F01-GM-38,070, awarded by National Institute of General Medical Sciences, NIH, Public Health Service. Male (9 specimens): 19.56 to 26.40 (21.83) long, 68 to 78 /L (72) maximum width. Anterior region of body 5.54 to 6.90 (5.96) long, with muscular pharynx 304 to 552 /L (425) long, followed by 40 to 59 (45) stichocytes. Posterior egion of body 13.84 to 19.50 (15.88) long. Ratio of anterior to posterior region 1:2.4 to 1:2.9 (1:2.7). Ratio of anterior region to total length 1:3.4 to 1:3.9 (1:3.7). Posterior extremity bears ventrally a small bursalike expansion and 2 small papillae. Body terminates in short blunt tail dorsally. Cloaca 3.31 to 3.70 (3.45) in length. Anus subterminal, surrounded by bursa. Spicule 2.22 to 2.96 (2.59) long, 12 to 17 /u (14) at maximum width, transversely striated, with blunt tip. Spicule sheath long, transversely striated, 18 to 26 / (22) at maximum width. Female (8 specimens): 29.15 to 36.46 (31.99) long, 77 to 100 ,u (87) at maximum width. Anterior region of body with muscular pharynx 276 to 684 /, (490) long, followed by 40 to 52 (48) stichocytes. Posterior region 24.51 to 30.29 (25.71) long. Ratio of anterior to posterior regions 1:3.4 to 1:4.9 (1:4.1). Ratio of anterior to total length 1:4.4 to 1:5.9 (1:5.1). Vulva 100 to 150 A (130) posterior to last stichocyte, anterior and posterior lips slightly salient. Anus subterminal. Posterior extremity slightly rounded and blunt, caudal papillae absent. Eggs unembryonated, 61 to 70 / (65) in length, 28 to 31 ,/ (30) in width. Holotype male: USNM Helm. Coll. No. 70563. Allotype female: USNM Helm. Coll. No. 70564. Paratypes: USNM Helm. Coll. No. 70565. Host: Coluber constrictor priapus Dunn and Wood, 1939. Location: Posterior region of oviducts; anterior end threaded into the mucosa, posterior region free in the lumen. Locality: Covington, Louisiana, USA 30?30' N, 90010' W. DISCUSSION The capillarids of cold-blooded vertebrates were thoroughly reviewed by Teixiera de Freitas and Lent (1935). In addition, Yama-

Capillaria blarinae, n. sp. (Nematoda: Trichuridae) from the Esophagus of the Short-Tailed Shrew, Blarina brevicauda (Say)

Retracted cirrus (spicule sheath) lined by short stout spines; length of spinous part of cloaca, 0.116-0.128; width, 0.012-0.014. Distance from anus to spicule pouch, or point of entrance of spicule, 0.165-0.204; spicule length, base to tip, 0.179-0.363; width, 0.0043-0.0072; ejaculatory duct, length, 0.36-0.46; width, 0.026-0.033; total length of cloaca, 0.38-0.46; width, 0.023-0.027. Cirrus usually not everted. Body, blunt posteriorly, ending in two knob-like enlargements bearing a transparent bursal membrane (Fig. 1-3). The ratio of esophagus length to body length was approximately 1 :2.4-1 :3.6. The structural plan (Fig. 7) was similar to Trichuris. The seminal vesicle proceeded posteriorly beside the narrow intestine. Near the last fourth of the body the seminal vesicle enlarged to become the muscular ejaculatory duct which opened into the proximal end of the thick walled cloaca. The cloaca was lined by a thin cuticular membrane continuous with the external cuticle. These structures were best seen when the male was placed in glycerin and viewed from the side. The spicule pouch entered the mid region of the cloaca and its lining fused with the cloacal lining. The spicule, tightly enclosed by the spicule pouch, was difficult to distinguish. However, critical focusing at different levels under oil immersion revealed the spicule as a translucent rod whose proximal part arose as a continuation of the retractor fiber at the base of the spicule pouch (Fig. 8). Measurement of the spicule length was made from this point to the rounded tip. The retractor fiber passed anteriorly and was fused to the body wall. Along its anterior length it received large muscle fibers from the body musculature (Fig. 9).

Notes on the Species of Capillaria Zeder, 1800 Known from Gallinaceous Birds

The species of the nematode genus, Capillaria Zeder, 1800, present many taxonomic difficulties. The most important of more recent studies regarding species in birds are those of Orosz (1931), Morgan (1932), Freitas & Almeida (1935a-b), Cram (1936) and Read (1949). Based upon large collections from gallinaceous and anatine game birds the present author (1945) tried to clear up the difficulties and confusions in the very scattered literature on these species. Since then I have found several new features especially concerning the species in gallinaceous birds. I consider it, therefore, of some use to summarize the results, and give a revised list of the species from these birds. The genus Capillaria comprises a large number of species. It would, therefore, be useful if it could be split into several genera. Some attempts have been made in this respect, beginning with Dujardin (1845). Baylis (1931) showed that the attempts up to that time had been futile, and this point of view was accepted by the above mentioned authors. Recently, L6pex-Neyra (1947), in a very comprehensive paper, revived some of the genera discarded by Baylis (1931), and erected some new ones. As principal characters for segregating the genera he used the ratio between the length of the esophagus, and of the entire body, and the presence or absence of spines on the spicule sheath. It is already doubtful to use differences in size, and even more ratios taxonomically. This is the more objectionable since he did not compute this ratio on the individual ratios, but took the first and last figure in the range of the length of the esophagus and of the posterior part of the body, respectively, computing the range of the ratio on these figures. For instance, in a table, p. 43, quoting measurements by Wehr (1939), on Capillaria obsignata, he found a range of the said ratio of 1.23-1.59; whereas the range, computed on the indivudal measurements is actually 1.20-1.88. For the main grouping in his key, p. 46-47, he used the feature, whether the esophagus constitutes less or more than one-third of the total length, and as subgrouping in both groups, spiny or non-spiny spicule sheath. If this key is strictly followed it should be possible to place, e.g. my specimens of Capillaria caudinflata in no less than four of his genera! (cf. Holger Madsen (1945, p. 15 and fig. 4)). I cannot, therefore, find an attempt at erecting subgenera or genera justified, when based upon the characters known at present, and prefer to adopt the opinion of Baylis. In the synopsis given by L6pez-Neyra, and by me in 1945, species described by Yamaguti (1941) and Johnston & Mawson (1941, 1945) are not included. In the following list the new points of view will be given under the heading of the individual species.

Studies on North American Helminths of the Genus Capillaria Zeder, 1800 (Nematoda): II. Additional Capillarids from Mammals with Keys to the North American Mammalian Species

As previously remarked by the writer in Part I of this study the worms of the genus Capillaria Zeder, 1800, do not show a marked degree of host specificity. Further evidence in favor of this view is afforded by the fact that C. americana n. sp., described in this paper, has been found in four different species of rodents. C. muris-sylvatici (Diesing, 1851) evidently also occurs in a variety of rodent hosts. Elton, Ford, and Baker (1931) in a study of the parasites of various rodent populations in England failed to find this worm in Microtus although these workers found it in other rodents. Conversely, the writer has found it only in material from Microtus in North America although large collections of parasites from a considerable number of different native rodents have been available for study. It seems probable that food habits are the chief factor determining the acquisition of infections with this species by rodents. Description or discussion of five species of Capillaria from North American mammals follows: Capillaria muris-sylvatici (Diesing, 1851) (Plate II, Figs. 10-13) Worms of this species were recovered from the small intestine of the vole, Microtus p. pennsylvanicus, examined at Madison, Wisconsin. No previous record from this host nor from any North American host has been found in a search of the literature. Since the worms show some features not recorded by other workers, a description of this material seems warranted. Description: Lateral bacillary lines visible. Mouth simple. Cuticle striated transversely. Female: 13.4 to 15.1 mm long; maximum width in posterior region 70 to 75 t. Termination of esophagus 3 mm from anterior end. Vulva just posterior to termination of esophagus, 3 to 3.2 mm from anterior end, with cuticular vulvar flap projecting from region of anterior labium. A discoid cuticular projection is located anterior to vulvar flap at level of esophageal termination. Vulva divides body 1: 3.5 to 1: 3.7. Ova 47 to 60 . long by 24 to 26 . wide; inner shell bends to form collar at each end; outer shell smooth. Anus slightly subterminal. Male: 9.1 to 10.8 mm long; maximum width 45 to 47 j. Termination of esophagus 2.7 to 2.9 mm from anterior end. Lateral caudal alae present, about 70 . long. Spicule 204 to 225 & long by 11 to 13 . wide. Spicule sheath without spines or transverse striations. Everted spicule sheath divided into four portions: Distal portion delicate, membranous, usually wrinkled; subdistal portion bulblike, muscular; proximal portion bulblike with rugose markings on lateral aspect; proximal and subdistal portions joined by short wrinkled tubular projection of proximal bulb. Cuticular bursa supported by pair of bifid papillae. Cloaca subterminal. Termination of esophagus divides body about 1:2.7.

Materials for a Monograph of the Ascons.—I. On the Origin and Growth of the Triradiate and Quadriradiate Spicules in the Family Clath-rinidæ

1. The first appearance of a calcareous spicule or spicular element, both ancestrally and in the actual development, was probably a minute vacuole in a cell of the dermal layer, filled with an organic substance perhaps identical with the intercellular ground substance, within which the minute sclerite appeared as a crystal or concretion. 2. The ancestral sclerite, though crystalline in structure, soon assumed a non-crystalline form as a whole, as an adaptation to its secondarily acquired function of support, and as it grew in size the contents of the vacuole formed the spicule sheath. 3. The ancestral form of spicule in the Calcarea was a simple monaxon, placed tangentially and completely embedded in the body-wall, lying between two adjacent pores. 4. From this ancestral spicule the forms of spicule now occurring in the Calcarea arose as follows: (a) the primitive monaxon acquired a distal portion projecting from the surface, as in the existing primary monaxons; (b) groups consisting each of three primitive monaxons became united by their contiguous ends to form a single triradiate system; (c) to some of the triradiate systems thus formed a fourth ray was added, secreted by the pore-cell, giving rise to the quadriradiate system ; (d) some of the triradiate systems, by loss of one ray and placing of the other two in a straight line, or by loss of two rays, perhaps became modified into secondary monaxon spicules. 5. The power of secreting a monaxon sclerite was primitively possessed by every cell of the dermal layer, and this condition appears to be retained in Leucosolenia. In Clathrina, on the other hand, all the skeletogenous cells migrate inwards from the dermal epithelium, and form a connective-tissue layer distinct in function from the contractile, undifferentiated dermal epithelium. In Leucosolenia also the actinoblasts of the triradiate systems form a deeper layer, but the dermal epithelium secretes primary monaxons--at least in the young form--and is non-contractile. 6. The forms of the spicules are the result of adaptation to the requirements of the sponge as a whole, produced by the action of natural selection upon variation in every direction.