Haemopis Marmorata Research Articles

Predatory Leeches (Hirudinida) May Contribute to Amphibian Declines in the Lassen Region, California

Researchers have documented precipitous declines in Cascades Frog (Rana cascadae) populations in the southern portion of the species' range, in the Lassen region of California. Reasons for the declines, however, have not been elucidated. In addition to common, widespread causes, an understanding of local community interactions may be necessary to fully understand proximal causes of the declines. Based on existing literature and observations made during extensive aquatic surveys throughout the range of R. cascadae in California, we propose that a proliferation of freshwater leeches (subclass Hirudinida) in the Lassen region may be adversely affecting R. cascadae populations. Leeches may affect R. cascadae survival or fecundity directly by preying on egg and hatchling life stages, and indirectly by contributing to the spread of pathogens and secondary parasites. In 2007, we conducted focused surveys at known or historic R. cascadae breeding sites to document co-occurrences of R. cascadae and leeches, determine if leeches were preying on or parasitizing eggs or hatchlings of R. cascadae, and identify the leech species to establish whether or not they were native to the region. We found R. cascade at 4 of 21 sites surveyed and freshwater leeches at 9 sites, including all sites with R. cascadae. In 2007 and 2008, the predatory leech Haemopis marmorata frequented R. cascadae egg masses, was observed probing or tearing at eggs on 24 occasions, and was 10 times more common in 1-m2 plots centered on egg masses than in similar plots without egg masses. Six species of leech were identified from the Lassen region, only 3 of which have been documented from the region prior to this study. Given our documentation of a diverse freshwater leech fauna in direct association with a precipitously declining species, we believe a better understanding of the biology and ecology of this poorly studied taxon is needed, in addition to studies of the effects of freshwater leeches on survival and recruitment of co-occurring amphibians.

Hyaluronidase activity in leeches (Hirudinea)

The leech hyaluronoglucuronidase (hyaluronidase I) was identified in Erpobdellidae ( Nephelopsis obscura and Erpobdella punctata) and Glossiphoniidae ( Desserobdella picta) and historically described from Hirudinidae ( Hirudo medicinalis). A second leech hyaluronidase (hyaluronidase II) which hydrolyzed only a few bonds to form hyaluronan oligosaccharides larger than 6500 Da, was found in Glossiphoniidae ( Helobdella stagnalis, Glossiphonia complanata, Placobdella ornata, and Theromyzon sp.) and in Haemopidae ( Haemopis marmorata). The distribution of the two hyaluronidases in leech occurred in both orders (Arhynchobdellida and Rhynchobdellida) and in macrophagous and haematophagous feeding types whereas the liquidosomatophagous leeches only had hyaluronidase II.

Macrobdella sestertia (Hirudinea: Hirudinidae) in Maine and a Key to the Hirudiniform Leeches of Maine

Macrobdella sestertia, a large rare leech, is reported from Maine for the first time. Prior to the Maine specimen, the species was known only from four specimens collected in Massachusetts. Currently, a total of four hirudiniform leech species, including the common but previously unreported Haemopis marmorata, are known from the state and are included in a key to hirudiniform species of Maine.

Serotonin depletion inhibits feeding in carnivorous leeches ( Haemopis)

The effect of reserpine on the serotonin content of the central nervous system and the feeding behavior of the carnivorous leech Haemopis marmorata was investigated. Leeches were hand-fed to satiation by presentation of pieces of chicken liver held in forceps for three meals at 4-day intervals prior to and 1 week following three consecutive injections of 100 micrograms reserpine in the crop. A group matched by weight and preinjection food intake was injected with the vehicle in a blind experimental design. Histochemical and chemical determinations showed that reserpine effectively depleted the serotonin content of the animal's central nervous system. Furthermore, the food intake of reserpine-treated animals was significantly less than that of the sham-injected group. However, the depleted animals continued to ingest approximately 40% of the amount consumed during the preinjection period. These results show that reserpine successfully depleted the serotonin in the carnivorous leech H. marmorata and decreased the food intake of this leech species. They suggest that feeding behavior in Haemopis is partially but not exclusively dependent on serotonin and that, in contrast to the sanguivorous leeches, additional factors may be necessary for its regulation.

Discriminative conditioning alters food preferences in the leech, Haemopis marmorata

The feeding behavior of the carnivorous leech, Haemopis marmorata, was aversively trained in a discriminative classical conditioning task. Two conditioned stimuli were used: One consisted of a food (chicken or liver) paired with an unconditioned stimulus of quinidine (bitter chemical); the other consisted of the alternate food presented in an unpaired relationship with the quinidine. Training consisted of alternating exposures to the two conditioned stimuli. Testing consisted of the simultaneous presentation of a conditioned stimulus food and a neutral food, beef. The percentages of responding to the conditioned stimuli were tabulated. Haemopis could discriminate between the conditioned stimuli. As a result of pairing a food with quinidine, the leeches selectively reduced their preference for that paired food, while they did not alter their preference for the unpaired food.

The opiate receptor: a single 110 kDa recognition molecule appears to be conserved in Tetrahymena, leech, and rat

We compared the molecular nature of the rat brain opiate receptor with that of the invertebrate leech, Haemopis marmorata, and the protozoan, Tetrahymena, in order to examine the issue of apparent receptor heterogeneity with respect to biochemical structure. A binding study with rat brain membrane verified that [ 125I]β-endorphin ([ 125I]βE), a broad specificity ligand, is displaced by the antagonist (-)-naloxone, but not the inactive stereoisomer (+)-naloxone; agonists considered prototypes for μ, δ, and κ opiate receptors all displayed stereospecific binding displacement. For SDS-PAGE analysis of the opiate receptor [ 125I]β-endorphin was covalently affixed to its recognition molecule with the cross-linking reagent DSS. Primary reaction products occur at 110, 58/55, and 29 kDa. Cross-linking products of all 3 molecular weights are effectively reversed by opiate ligands, regardless of their μ, δ, or κ specificities. Peptide mapping studies in SDS gels, using limited proteolysis, showed that the 110 kDa band can be digested into 58 and 29 kDa fragments and the 58 kDa band into a 29 kDa fragment. Additional smaller molecular weight fragments were generated from the 110, 58/55, and 29 kDa bands which shared their molecular weights. Two possible explanations for the extensive homology between the three major cross-linking products are: (1) the 110 kDa species is the opiate receptor, and the 58 and 29 kDa species are proteolytic fragments; and (2) one of the lower molecular weight species is the opiate receptor, and adjacent receptors are aggregated into the 110 kDa complex through cross-linking. An evolutionary conservation of the opiate receptor is suggested by the presence of the same 3 major cross-linking products in Tetrahymena, leech, and rat.

The effects of procaine, strychnine and penicillin on nociceptive neurons in leech segmental ganglia

1. 1. Procaine, strychnine and penicillin selectively depolarized the membrane potential and prolonged the action potential recorded in the lateral but not the medial nociceptive (N) cell in the hiruclinid leech Macrobdella decora. 2. 2. In contrast, procaine did not differentiate between medial and lateral N cells in two other hiruclinid leeches Hirudo medicinalis and Haemopis marmorata. In these species, the drug equally decreased the amplitude of action potentials in both types of N cells without effecting their resting membrane properties. 3. 3. In the nociceptive neurons of the glossiphoniid leech Haementeria ghilianii which possesses only one type of N cell, procaine produced a depolarization and prolonged the action potential. This finding indicates that the single pair of N cells in Haementeria is of the lateral type. 4. 4. The results suggest that the lateral type N cell in Macrobdella and Haementeria share a unique Na +-dependent conductance which is selectively opened by the local anesthetics procaine and strychnine as well as by penicillin. This conductance is either not present or insensitive to the drugs in the homologous N cells in the two other leech species examined.

Segmental differentiation in the leech nervous system: the genesis of cell number in the segmental ganglia of Haemopis marmorata.

In hirudinid leeches, the segmental ganglia associated with the sexual organs contain several hundred more neurons than other midbody ganglia. To determine whether this difference arises by differential cell addition or by differential cell death, cell counts were made in several segmental ganglia during the course of embryonic and postembryonic development. The results show that all ganglia behave equally in early development. In each case, at least 10-20% more cells than will make up the adult complement of about 400 neurons is generated, and by about 20 days of embryonic development cell loss brings the number down to about 400 cells. By about 30 days, when animals emerge from their cocoons, additional cells have begun to appear in the sex ganglia. The number of extra cells continue to increase gradually over the next several months, until the adult number of 600-700 neurons is attained. These observations indicate that at least some segmental differences in the size of neuronal populations are due to differential cell proliferation and that these differences can arise quite late in the maturation of an animal.

Antibody staining reveals novel aspects of segmentation within the leech central nervous system

The leech is a segmented annelid with a well characterized central nervous system. In this report, we use antibodies to map the distribution of neurons confined to selected segmental ganglia in the mud leech Haemopis marmorata. The distribution patterns of these neurons suggest 3 novel aspects of segmentation in the leech nervous system: (1) neurons are assigned to even-numbered ganglia through a mechanism which effectively counts through the leech segmental body plan by units of 2, (2) neurons are assigned to ganglia 7 and 14 through a mechanism which effectively counts in units of 7 and (3) neurons are assigned to the 2nd of 4 fused head ganglia and to the 2nd of 21 unfused midbody ganglia through a mechanism which effectively counts units from the origin of these 2 ganglia ic series. These 3 hypothetical counting mechanisms divide the central nervous system (CNS) into supersegmental units. Neurons used to define these supersegmental units have been injected with tracer and identified as interganglionic interneurons. Competitive interactions among embryonic precursors of these neurons may directly eliminate their homologs from intervening ganglia, and thus sculpture supersegmental patterns into the mature nervous system.

The embryonic development of peripheral neurons in the body wall of the leech Haemopis marmorata

The appearance of peripheral neurons within the skin during embryonic development of the leech is described. These neurons were labeled using a monoclonal antibody, Lan3-6, which recognizes antigens in both the cell body and the axons of these cells. Within the 5 annuli that are found in each midbody segment, peripheral neurons first label in the middle and last in the most anterior and posterior ones. In each annulus, the number of cells labeled is initially 4 and increases as development proceeds. By the end of embryogenesis, all annuli show approximately equal numbers of Lan3-6 labeled neurons. The development of peripheral neurons in the skin of the rear sucker is also described.

Monoclonal antibody identifies a 63,000 dalton antigen found in all central neuronal cell bodies but in only a subset of axons in the leech.

The monoclonal antibody Lan3-8 binds to all the neuronal cell bodies in midbody, head, tail, and supraesophageal ganglia in the mud leech (Haemopis marmorata) and the medicinal leech (Hirudo medicinalis). In contrast to the general distribution of the antigen in cell bodies it is only found in a subset of axons, where electron microscopy suggests that it may be associated with a cytoskeletal filament system. Immunoblotting shows that the antibody binds to a 63,000 dalton band that is protease-sensitive. The same 63 kilodalton (kd)-antigen is found in all regions of the central nervous system, in proteins isolated from connectives (axons alone), and from hand-dissected identified cell types. The molecular weight and electron microscopic localization raised the possibility that this antigen is the core neurofilament protein, but the antigen does not comigrate with 67-kd intense coomassie blue band that binds another anti-intermediate filament antibody. The supraesophageal ganglia are known to have a different developmental or origin from the other structures in the leech central nervous system. Two-dimensional gel electrophoresis and silver staining show that, like the 63-kd antigen, many other proteins are very similar in these developmentally distinct neural structures.

Axonal projections of mechanosensory neurons in the connectives and peripheral nerves of the leech, Haemopis marmorata.

The axonal projections of the seven mechanosensory neurons in the connectives and peripheral nerves were examined by horseradish peroxidase (HRP) injections. In the connective the closely functionally related mechanosensory neurons travel in two bilaterally symmetrical regions, which comprise less than 10% of the connective's cross-sectional area. This grouping may reflect the similar functional properties and synaptic connections of the cells. Serial sections through the neuropil-connective junction zone showed that the organization of the axons is independent of glial fasciculation. Fascicles are not rigid structures; they were found to part and fuse in a seemingly random manner. The glial cell seems therefore to have only a supportive structural function and not to play any role in axonal guidance or to define any specific nerve fascicles in the leech. The projections of the mechanosensory cells in the peripheral roots were not as stereotyped as in the connective. However, examination of the branching of the medial and lateral P cells in the posterior root showed that the roots are highly structured and that some axons may be confined to tracts which have specific positions related to the branching of the root. The possible role of the P cells in pioneering these tracts is discussed.

Host-Parasite Relationships of Helminth Parasites in Leeches of the Genus Haemopis. I. Associations at the Individual Host Level

Specimens of six species of leeches of the genus Haemopis were necropsied and examined histologically in an attempt to elucidate the in situ host-parasite relationships between the leeches and their helminths. Specimens of five species of mature trematodes were recovered from the gastrointestinal ceca. The histological organization of the gastrointestinal ceca was found to be quite similar to that of the small intestine of ictalurid fishes, and it is suggested that ancestral macroderoidid parasites of leeches may have been preadapted to the intestinal environment of catfishes. This explanation is proposed to account for the continued existence of members of the genus Alloglossidium in the intestine of both piscine and hirudinean hosts. Extreme interand intraspecific crowding of enteric trematodes also was observed; a possible mechanism for reduction of competition through habitat partitioning is examined. Immature trematodes and nematodes were observed to be encysted along the blood vessels of the gastrointestinal ceca. A nonspecific fibrous encapsulation response to these cysts was observed frequently; in some cases, this host response appeared to induce disintegration of the larval trematodes. Six species of mature digenetic trematodes from leeches of the genus Haemopis Savigny, 1822 have been described recently (Demshin, 1968; Fish & Vande Vusse, 1976; Neumann & Vande Vusse, 1976; Schmidt & Chaloupka, 1969; Timmers, 1979). With the exception of a brief description of the attachment of some of these trematodes to the host intestinal wall (Taft & Kordiyak, 1973), no effort has been made to examine the nature of these unusual host-parasite systems. Therefore, studies were undertaken in an attempt to describe the in situ relationships between helminth parasites, both enteric and parenteric, and leeches of the genus Haemopis. Data on prevalence, abundance, and host-specificity also were obtained and are presented in part II (Riggs & Ulmer, 1983). MATERIALS AND METHODS Leeches were collected at night during late spring and early summer of 1976 and 1977 in the shallows and from marshy shorelines of several lakes 1We would like to thank Drs. Frederick Vande Vusse, Roy T. Sawyer, Marvin Meyer, and L. R. Richardson for contributing their knowledge of and experience with the hirudineans and their parasites. We are especially grateful to Dr. Gerald W. Esch for his careful reviews of the manuscript and his helpful suggestions during its preparation. 2 Publication costs, in part, are being met by a grant from the Spencer-Tolles Fund of the American Microscopical Society. 3 Present address: Department of Biology, Wake Forest University, Winston-Salem, North Carolina 27109, U.S.A. TRANS. AM. MICROSC. SOC., 102(3): 213-226. 1983. () Copyright, 1983, by the American Microscopical Society, Inc. This content downloaded from 157.55.39.180 on Tue, 27 Sep 2016 05:27:58 UTC All use subject to http://about.jstor.org/terms TRANS. AM. MICROSC. SOC. and ponds located in north-central Minnesota and northwestern Iowa. Necropsies were conducted 24-48 h after collections; gross observations on living worms in tlhe host gut were made using a stereo microscope equipped with 30x and 60x magnification. The techniques of Fried et al. (1970) were employed in the study of encysted metacercariae. The posterior one-third of the intestines of five specimens each of Haemopis marmorata (Say, 1824) Moore, 1901, H. grandis (Verrill, 1874), H. plumbea Moore, 1912 were removed, extended, and fixed in 10% buffered-formalin at 70?C and embedded in paraffin. Sagittal sections of the intestines from two specimens of each host species were cut serially at 10 /m and the remaining intestinal preparations were sectioned tranversely at 15 /um. All sections were stained in Harris' hematoxylin and eosin Y.

The expression of antigens by embryonic neurons and glia in segmental ganglia of the leech Haemopis marmorata

Monoclonal antibodies (mAbs) raised against adult leech nervous systems were screened on embryos of the leech Haemopis marmorata in order to determine when in development specific antigens are first expressed and the order in which they are expressed by different cells or tissues. Three of the mAbs produced by Zipser and McKay (Zipser, B., and R. McKay (1981) Nature 289: 549-554) were screened: Lan3-1, Lan3-5, and Lan3-6. Each mAb shows a different pattern of labeling in the adult leech nerve cord (Zipser, B. (1982) J. Neurosci. 2: 1453-1464). The embryonic stages studied were from 5 days after egg deposition to 30 days (emergence from the cocoon). The pattern of labeling was assayed in whole mounts using horseradish peroxidase-conjugated second antibodies. The principal results are as follows. (1) Antigens recognized by Lan3-5 are first expressed by the glia of the roots of the anterior segmental ganglia at 6 to 7 days, several days later by the interganglionic connective glia, and near the end of embryonic development by ganglionic neurons. An anterior to posterior temporal gradient is observed in the expression of these antigens. In addition, Lan3-5 also labels the protonephridia and nephridia from early development onward. (2) Antigens recognized by Lan3-6 are first expressed by a pair of neurons in each segmental ganglion and later in development by additional neurons. By the time of emergence, however, only about half of the neurons that label in the adult have done so, implying that some neurons express these antigens postembryonically. Labeling with Lan3-6 is first seen in neuronal somata and only later in neuronal processes. (3) Antigens recognized by Lan3-1 and expressed by segmentally specific neurons in ganglia 5 and 6 are not detectable during embryonic development, but are so at early postembryonic stages. Thus, these three mAbs provide an approach to study different aspects of the development of the leech nervous system, specifically the relation between glial and neuronal differentiation and the genesis of segmentally specific phenotypes.

Host-Parasite Relationships of Helminth Parasites in Leeches of the Genus Haemopis. I. Associations at the Individual Host Level

Specimens of six species of leeches of the genus Haemopis were necropsied and examined histologically in an attempt to elucidate the in situ host-parasite relationships between the leeches and their helminths. Specimens of five species of mature trematodes were recovered from the gastrointestinal ceca. The histological organization of the gastrointestinal ceca was found to be quite similar to that of the small intestine of ictalurid fishes, and it is suggested that ancestral macroderoidid parasites of leeches may have been preadapted to the intestinal environment of catfishes. This explanation is proposed to account for the continued existence of members of the genus Alloglossidium in the intestine of both piscine and hirudinean hosts. Extreme interand intraspecific crowding of enteric trematodes also was observed; a possible mechanism for reduction of competition through habitat partitioning is examined. Immature trematodes and nematodes were observed to be encysted along the blood vessels of the gastrointestinal ceca. A nonspecific fibrous encapsulation response to these cysts was observed frequently; in some cases, this host response appeared to induce disintegration of the larval trematodes. Six species of mature digenetic trematodes from leeches of the genus Haemopis Savigny, 1822 have been described recently (Demshin, 1968; Fish & Vande Vusse, 1976; Neumann & Vande Vusse, 1976; Schmidt & Chaloupka, 1969; Timmers, 1979). With the exception of a brief description of the attachment of some of these trematodes to the host intestinal wall (Taft & Kordiyak, 1973), no effort has been made to examine the nature of these unusual host-parasite systems. Therefore, studies were undertaken in an attempt to describe the in situ relationships between helminth parasites, both enteric and parenteric, and leeches of the genus Haemopis. Data on prevalence, abundance, and host-specificity also were obtained and are presented in part II (Riggs & Ulmer, 1983). MATERIALS AND METHODS Leeches were collected at night during late spring and early summer of 1976 and 1977 in the shallows and from marshy shorelines of several lakes 1We would like to thank Drs. Frederick Vande Vusse, Roy T. Sawyer, Marvin Meyer, and L. R. Richardson for contributing their knowledge of and experience with the hirudineans and their parasites. We are especially grateful to Dr. Gerald W. Esch for his careful reviews of the manuscript and his helpful suggestions during its preparation. 2 Publication costs, in part, are being met by a grant from the Spencer-Tolles Fund of the American Microscopical Society. 3 Present address: Department of Biology, Wake Forest University, Winston-Salem, North Carolina 27109, U.S.A. TRANS. AM. MICROSC. SOC., 102(3): 213-226. 1983. () Copyright, 1983, by the American Microscopical Society, Inc. This content downloaded from 157.55.39.180 on Tue, 27 Sep 2016 05:27:58 UTC All use subject to http://about.jstor.org/terms TRANS. AM. MICROSC. SOC. and ponds located in north-central Minnesota and northwestern Iowa. Necropsies were conducted 24-48 h after collections; gross observations on living worms in tlhe host gut were made using a stereo microscope equipped with 30x and 60x magnification. The techniques of Fried et al. (1970) were employed in the study of encysted metacercariae. The posterior one-third of the intestines of five specimens each of Haemopis marmorata (Say, 1824) Moore, 1901, H. grandis (Verrill, 1874), H. plumbea Moore, 1912 were removed, extended, and fixed in 10% buffered-formalin at 70?C and embedded in paraffin. Sagittal sections of the intestines from two specimens of each host species were cut serially at 10 /m and the remaining intestinal preparations were sectioned tranversely at 15 /um. All sections were stained in Harris' hematoxylin and eosin Y.

Number and distribution of neurons in leech segmental ganglia

The number of neurons and their distribution were determined for specific segmental ganglia from the nerve cord of four different species of leech. Quantitative data were obtained by using computer-aided techniques for the analysis of nerve structure from serially sectioned or whole-mounted tissue. The species studied were Hirudo medicinalis, Macrobdella decora, Haemopis marmorata (family Hirudinidae), and Haementeria ghilianii (family Glossophoniidae). Two sets of ganglia were studied in each species: middle ganglia (9, 10, and 11) and sex ganglia (5 and 6). The middle ganglia, as well as the rest of the 21 segmental ganglia, except 5 and 6, are thought to be quite similar. The sex ganglia are associated with the sexual organs and appear to have more neurons. The data reported here indicate that: a) the number of neurons in a specified ganglion varies by one to two percent from animal to animal of a given species; b) the middle ganglia of a particular leech each have approximately the same number of neurons, with a variation also within two percent; c) the middle ganglia of Hirudo, Macrobdella, and Haemopis have nearly the same number of neurons (about 400), but those of Haementeria have some 20 fewer (about 380); d) the sex ganglia of Hirudo, Macrobdella, and Haemopis have a few hundred more neurons than their middle ganglia, with the exact number varying according to the species, but the sex ganglia in Haementeria have only about 20 more neurons than their middle ganglia; e) the distribution of neuronal somata among glial packets is not symmetric about the midsaggital plane of the animal, and the number of somata in each packet is variable; and f) the geometry of the glial packets is generally invariant, but occasionally packets are found in abnormal positions.

On neuronal homologies within the central nervous system of leeches

1. 1. We investigated the electrophysiological properties of 18 identifiable neurons in three leeches: Haemopis marmorata, Hirudo medicinalis and Macrobdella decora. 2. 2. The paired serotonergic Retzius cells are indistinguishable among the species in terms of somata positions, branching patterns, electrophysiological parameters and muco-effector functions. 3. 3. The T, P and N mechanosensory cells in these three species are virtually identical by virtue of their sizes, locations, axonal branching, electrophysiological properties, responses to dermal stimulation and receptive fields. 4. 4. The L motor neurons of all the leeches are electrotonically coupled, have equivalent cell positions and axonal branches, and control the longitudinal muscles. 5. 5. We have investigated several properties of 12 neurons in Hirudo and Haemopis and found no differences between their S interneuron, heart excitor motor neurons and their monoamine-containing neurons. 6. 6. We found no differences between 30 homologous neurons in the C.N.S. of these leeches at any level of organization: membrane properties, central connectivity, morphology and axonal branching, peripheral connectivity or functional roles. The extremely conservative stereotypy of these cells is impressive.

New records and species of leeches (Annelida: Hirudinea) from North and South Carolina

Summary Twenty freshwater, one euryhaline, one terrestrial, and six marine leeches are now known to occur in the Carolinas. Haemopis septagon, the second terrestrial leech discovered in North America, and five aquatic taxa—Placobdella nuchalis, P. translucens, Mooreobdella melanostoma, M. tetragon, and Erpobdella punctata coastalis—are previously undescribed. Specimens of Placobdella papillifera and P. multilineata, are examined in detail. Four additional species—Batracobdella phalera, B. picta, Helobdella elongata and Haemopis marmorata—have been found in the Carolinas for the first time. The distribution of leeches in the Carolinas is determined in part by the boundaries of the three physiographic provinces. Batracobdella picta, Oligobdella biannulata, and Haemopis marmorata occur only in the Appalachian Mountains, while Placobdella nuchalis, P. translucens, Glossiphonia swampina, Batracobdella phalera, Helobdella stagnalis, H. elongata and Macrobdella ditetra were found only in the coastal plain. Along with the physiographic determinants of distribution, there are also north-south factors of interest. The coastal plain species Philobdella gracilis, also found in the piedmont plateau, and Macrobdella ditetra are southern species which reach the northern limit of their range in North Carolina. On the other hand, Batracobdella picta, Erpobdella punctata punctata, Haemopis marmorata, and Macrobdella decora are common northern leeches and reach their southern limit in the area. Still other species—Placobdella nuchalis, Glossiphonia swampina, Oligobdella biannulata, Erpobdella punctata coastalis, Mooreobdella melanostoma, M. tetragon, and Haemopis septagon—appear to be highly localized and are currently known only from the Carolinas, extending into southeastern Virginia in the case of H. septagon (Shelley, 1975). Observations of locomotion and other behaviour in the biannulate leech, Oligobdella biannulata, reveal a lack of muscular activity in the mid-body regions, which may partially explain the significance of the biannulate condition. This species has been found to have more than one desmognathine salamander host in nature. A key to the hirudinifauna of the Carolinas, both known and expected, has been formulated.

Leeches (Hirudinea) in the Upper Stones River Drainage of Middle Tennessee

Leeches were collected from September 1972 through November 1973 from 68 sites, and measurements were made of water temperature, pH and dissolved oxygen. Eight species were collected representing four families: Erpobdellidae, Glossiphoniidae, Hirudinidae and Piscicolidae. Placobdella ornata was the most widely distributed and eurytopic species, and contrary to previous reports of its principal occurrence on turtles, 98% of the specimens were free-living. Placobdella parasitica was the most abundant species, and 89% were attached tol the turtles Chelydra serpentina and Pseudemys scripta. Haemopis marmorata exhibited stenotopic characteristics and was the only species not associated with any other species. Illinobdella moorei occurred mainly on the bass species, Micropterus dolomieui and M. salmoides, but it was also found on Etheostoma squamiceps and Notropis cornutus, which are new host records. Erpobdella punctata, Haemopis marmorata, Helobdella elongata and Placobdella ornata are new records for Tennessee. Helobdella lineata occurred at four sites, and Illinobdella alba at only one site. INTRODUCTION The Hirudinea constitute a significant part of the North American fresh-water fauna, but apart from the study of Louisiana leeches by Sawyer (1967), they have received only scant attention in the southeastern U.S.A. No study has been published previously which dealt exclusively with leeches of Tennessee, but the literature does record six species from the state: Haemopis terrestris (Moore, 1898), Helobdella lineata (Sawyer, 1972), Illinobdella alba, I. moorei, I. richardsoni (Bangham and Venard, 1942; Meyer, 1946) and Placobdella parasitica (Moore, 1898; Sawyer, 1972). A preliminary search for leeches in the Stones River drainage of Middle Tennessee yielded two previously unreported species from the state. The objectives of the present study were to identify the leech species and their distribution in the upper drainage of Stones River, to make some ecological observations, and to establish a base for future studies on Tennessee leeches. DESCRIPTION OF STUDY AREA The Stones River basin ig located in the N-central portion of the Nashville or Central Basin, a physiographic province of Middle Tennessee that presents a gently undulating plain ranging in altitude from 152 to 213 m and that is developed on soluble Ordovician limestone (Bassler, 1932). Stones River and its tributaries receive drainage from five counties: Cannon, Davidson, Rutherford, Williamson and Wilson.

Effects of temperature upon the electrophysiology of retzius cells in the leech

1. 1. The Q 10 temperature coefficients of several electrophysiological parameters of Retzius cells were examined by microelectrode recording in segmental ganglia from the horse leech, Haemopis marmorata (Say), at temperatures between 5 and 25°C. 2. 2. The action potential characteristics of Retzius cells have temperature coefficients which are suggestive of processes mediated by chemical reactions: duration, 3.1; rate of rise, 3.8; rate of decline, 2.3; and amplitude of the after-potential, 2.5. 3. 3. The membrane and electrotonic characteristics have coefficients which are suggestive of physical or diffusional processes: membrane resistance varies with temperature ( Q 10, 1.55) while the attenuation factor ( Q 10, 1.25) and resistance of the electrotonic junction ( Q 10, 1.05) vary inversely with temperature. 4. 4. An analysis of the impulses in either Retzius cell and of the electrotonic depolarization of the homologous neuron indicates that the cell pair is functionally asymmetric and their loci of impulse initiation are more distant from their neurosomata than their electrotonic junction.