Van Der Schalie Research Articles

Global SMOS Soil Moisture Retrievals from The Land Parameter Retrieval Model

A recent study by Van der Schalie et al. (2015) showed good results for applying the Land Parameter Retrieval Model (LPRM) on SMOS observations over southeast Australia and optimizing and evaluating the retrieved soil moisture (θ in m3m−3) against ground measurements from the OzNet sites. In this study, the LPRM parameterization is globally updated for SMOS against modelled θ from MERRA-Land (MERRA) and ERA-Interim/Land (ERA) over the period of July 2010–December 2010, mainly focusing on two parameters: the single scattering albedo (ω) and the roughness (h). The Pearson's coefficient of correlation (r) increased rapidly when increasing the ω up to 0.12 and reached a steady state from thereon, no significant spatial pattern was found in the estimation of the single scattering albedo, which could be an artifact of the used parameter estimation procedure, and a single value of 0.12 was therefore used globally. The h was defined as a function of θ and varied slightly for the different angle bins, with maximum values of 1.1–1.3 as the angle changes from 42.5° to 57.5°.This resulted in an average r of 0.51 and 0.47, with a bias (m3m−3) of −0.02 and −0.01 and an unbiased root mean square error (ubrmse in m3m−3) of 0.054 and 0.056 against MERRA (ascending and descending). For ERA this resulted in an r of 0.61 and 0.53, with a bias of −0.03 and an ubrmse 0.055 and 0.059. The resulting parameterization was then used to run LPRM on SMOS observations over the period of July 2010–December 2013 and evaluated against SMOS Level 3 (L3) θ and available in situ measurements from the International Soil Moisture Network (ISMN). The comparison with L3 shows that the LPRM θ retrievals are very similar, with for the ascending set very high r of over 0.9 in large parts of the globe, with an overall average of 0.85 and the descending set performing less with an average of 0.74, mainly due to the negative r over the Sahara. The mean bias is 0.03, with an ubrmse of 0.038 and 0.044. In this study there are three major areas where the LPRM retrievals do not perform well: very dry sandy areas, densely forested areas and over high latitudes, which are all known limitations of LPRM. The comparison against in situ measurement from the ISMN give very similar results, with average r for LPRM of 0.65 and 0.61 (0.64 and 0.59 for L3) for the ascending and descending sets, while having a comparable bias and ubrmse over the different networks. This shows that LPRM used on SMOS observations produce θ retrievals with a similar quality as the SMOS L3 product.

Phylogenetic Analysis of the Freshwater Mussel GenusPtychobranchus(Bivalvia: Unionidae)

The phylogenetic relationships of species of the mussel genus Ptychobranchus Simpson, 1900 were examined using the mitochondrial DNA sequences of the ND1 and 16S gene regions. A total of 31 individuals representing the five species are included in this analysis. Outgroups were drawn from other unionid genera previously shown to be closely related to Ptychobranchus. Phylogenetic analysis was conducted using Bayesian methods applying several data-partitioning strategies. The results of all analyses support the monophyly of Ptychobranchus, and the interrelationships of its constituent species are consistent across all analyses. Ptychobranchus occidentalis (Conrad, 1836) is recovered as paraphyletic with P. fasciolaris (Rafinesque, 1820). Molecular analyses indicate that Ptychobranchus jonesi van der Schalie, 1934 is a member of the genus, and character state reconstruction predicts that it should possess the complex conglutinate that is found in other species of Ptychobranchus.

Farewell Editorial

Farewell Editorial

Hermaphroditism in the Iridinidae (Bivalvia: Etherioidea)

The predominant reproductive mode for the Unionoida is hypothesised to be dioecy (gonochorism), with hermaphroditism sporadically distributed within the order. However, since the reproductive modes of unionoidean bivalves have been relatively well documented in comparison to the situation within the Etherioidea, additional data on the reproductive patterns of the latter are necessary to test this generality. A summary of the historic works dealing with hermaphroditism in North American and European Unionidae was presented by Van der Schalie. Within the North American fauna, a relatively large number of dioecious species exhibit a low incidence of hermaphroditic individuals, while a smaller number of species are typically hermaphroditic. Of the ca 300 unionoid species in North America, only seven species have been Figure 4. Daily population size estimates based on the modified Lincoln index. Vertical bars give standard errors of population estimates. The dashed horizontal line shows the total number of individuals found (Fig. 3). Estimates could not be calculated for surveys 9 and 10, because no new individuals were found. Figure 3. Cumulative number of individual sea slugs recorded over our ten-day survey. Open circles indicate observations at high tide, filled ones observations at low tide. ACKNOWLEDGEMENTS

Animals as sentinels of human health hazards of environmental chemicals.

A workshop titled "Using Sentinel Species Data to Address the Potential Human Health Effects of Chemicals in the Environment," sponsored by the U.S. Army Center for Environmental Health Research, the National Center for Environmental Assessment of the EPA, and the Agency for Toxic Substances and Disease Registry, was held to consider the use of sentinel and surrogate animal species data for evaluating the potential human health effects of chemicals in the environment. The workshop took a broad view of the sentinel species concept, and included mammalian and nonmammalian species, companion animals, food animals, fish, amphibians, and other wildlife. Sentinel species data included observations of wild animals in field situations as well as experimental animal data. Workshop participants identified potential applications for sentinel species data derived from monitoring programs or serendipitous observations and explored the potential use of such information in human health hazard and risk assessments and for evaluating causes or mechanisms of effect. Although it is unlikely that sentinel species data will be used as the sole determinative factor in evaluating human health concerns, such data can be useful as for additional weight of evidence in a risk assessment, for providing early warning of situations requiring further study, or for monitoring the course of remedial activities. Attention was given to the factors impeding the application of sentinel species approaches and their acceptance in the scientific and regulatory communities. Workshop participants identified a number of critical research needs and opportunities for interagency collaboration that could help advance the use of sentinel species approaches.

Stability of Recent Unionid (Mollusca: Bivalvia) Communities Over the Past 6000 Years

Historically, the greatest freshwater bivalve species diversity in the world was in the Tennessee, Cumberland and Alabama River systems. The Tennessee River System had 94 and the Cumberland River System had 85 taxa reported (Starnes and Bogan, 1988). Ortmann (1918, 1924, 1925, 1926), Wilson and Clark (1914), Neel and Allen (1964), van der Schalie (1939, 1973) and van der Schalie and van der Schalie (1950) documented this diverse fauna. However, even in the early days of this century these authors noted the decline in the mussel populations and the loss of species from certain rivers (e.g. Ortmann, 1909a, 1918).

Mollusca of the White River, Arkansas and Missouri

-The White River of Arkansas and Missouri formerly supported a numerous and diverse assemblage of freshwater Mollusca. Reservoir construction, channelization, and other methods of stream regulation have altered the basin extensively. Of the approximately 100 species once knwn from the White River system, 64 species have been collected during recent sampling from the primary channel of the river. The remainder of the molluscan fauna appears to have been extirpated from the main channel. Isolated populations of these species may still occur in some of the tributaries. The decline of the freshwater molluscan populations, particularly mussels, became a major concern shortly after the beginning of the 20th century. The cause and interest at that time were both generated by the use of the shells in the manufacturing of buttons and, to a lesser extent, the collecting of pearls (Coker, 1919). This resulted in some of the major studies conducted on the freshwater fauna of the United States (e.g., Lefevre and Curtis, 1912; Meek and Clark, 1912; Wilson and Clark, 1914; Coker et al., 1921). The concern was again voiced by Ortmann (1924) over the damming of Mussel Shoals. Today, primary threats to the American fauna are derived from pollution, stream alteration, and the effects related to the encroachment by Corbicula, although a commercial market for shells has again developed due to the Japanese cultured pearl industry (Van der Schalie, 1969). This paper presents a preliminary overview of the alteration to the White River in Arkansas and Missouri and the resultant effects on the molluscan assemblages. STUDY AREA.-The White River is approximately 1,210 km long with a drainage basin of 72,520 km2 (Fig. 1). It originates on the northern slope of the Boston Mountains, the southernmost of the Ozark Plateaus, in northwestern Arkansas and flows northeasterly into south-central Missouri. It then follows a southeasterly route back into Arkansas and leaves the Ozarks near Batesville, Arkansas, a short distance upstream from the confluence of the Black River. The last 420 km of the river are a lowland stream in the Mississipi Alluvial Valley. This channel represents a former course of the Mississippi River (Gordon et al., 1980). Improvement of the White River for navigation was begun in 1871 by the Army Corps of Engineers. Projects were authorized by the River and Harbor Act of 1892 for development from the mouth to Forsyth, Missouri. A series of locks and dams above Batesville were authorized in 1899, but never completed. The effective head of navigation became Batesville (river km 484). The navigation channel is now maintained from Newport, Arkansas (river km 418), to the mouth at an annual coast of about $1,000,000. It is navigable about 75% of the year. A recent proposal to deepen and widen the channel has been abandoned due to prohibitive costs (US Army, 1965; Griffee, 1980). The Ozark portion of the river has been dammed five times between river km 675 and 1125. These were built from the late-1940's througth the mid-1960's and include four Army Corps of Engineers projects and a small municipal facility. These are, in an upstream progression, Bull Shoals, Taneycomo, Table Rock, and Beaver reservoirs, which all utilize hypolimnetic release, and the city of Fayetteville's Lake Sequoyah. The headwaters of the White River lie above Lake Sequoyah. This area has been moderately affected by pollution and some gravel removal. The This content downloaded from 157.55.39.163 on Wed, 21 Sep 2016 05:37:22 UTC All use subject to http://about.jstor.org/terms The Southwestern Naturalist

Meristograms: Graphical Analysis of Serial variation of Proboscis Hooks of Echinorhynchus (Acanthocephala)

Huffman, D. G., and W. L. Bullock (Aquatic Biology Station, Southwest Texas State University, San Marcos, Texas 78666 and Zoology Department, University of New Hampshire, Durham, New Hampshire 03824) 1975. Meristograms: graphical analysis of serial variation of proboscis hooks of Echinorhynchus (Acanthocephala). Syst. Zool. 24:333345.-Some of the problems associated with the taxonomic study of proboscis hook characteristics in the phylum Acanthocephala are discussed. The Meristogram method of graphical analysis is introduced and applied to the genera Echinorhynchus and Pomphorhynchus. This new method eliminates many of the problems associated with the study of morphological variability in the serially repeating proboscis hooks of these acanthocephalans. Suggestions are made concerning the application of the method to other groups possessing serially repeating structures such as Annelida, Arthropoda, Graptoloidea and Osteichthyes. [Meristograms; segmentation; Acanthocephala.] During a study of morphological variability in the acanthocephalan genus Echinorhynchus, subtle but apparently consistent differences were detected between the probosces of certain collections of these worms from marine fishes of New England. The origin of these differences was later attributed to the way in which hook morphology changes from anterior to posterior along the probosces. Attempts to compare the above collections with regard to these differences in hook shape distribution using traditional methods were unsatisfactory due to the following complicating factors: (1) differing numbers of hooks per row on probosces under comparison which prohibited direct comparisons of hook shape distribution; (2) conspicuous size differences between homologous hooks of different worms which sometimes suggested shape differences where there were none or obscured actual shape differences; (3) lack of directly measurable hook characters which approached a quantification of shape; and (4) lack of available methods for combining the rates of positional variation in a given hook character for several probosces 'This paper received the Phi Sigma Henry Vander Schalie Research Award for 1975. so as to obtain a representative average rate of positional variation for an entire collection. The graphical method developed herein largely eliminates the above problems. It results in the ,generation of a graphical pattern, or meristogram, the appearance of which is an abstract but sensitive representation of the average rate of positional variation in hook morphology from anterior to posterior on the probosces of a collection

Discovery of the Carolina Marsh Clam, Polymesoda caroliniana (Bosc), A Supposed Florida Disjunct Species, in Everglades National Park, Florida

The presence of disjunct species of animals on either side of the Florida peninsula has been reported by a number of authors. The littorinid mollusk, Littorina irrorata Say, which has a range from Massachusetts to the Rio Grande of Texas, except for south Florida, is one such species (Bequaert 1943). The marsh crab, Sesarma cinereum (Bosc), is another example of an animal with a distribution from Virginia to the western Gulf of Campeche except for a break in southern Florida (Rathbun, 1918). Williams (1965) lists 23 species of crustaceans having interrupted distribution at the Florida peninsula. This report on discovery of a breeding population of the Carolina marsh clam, Polymesoda caroliniana (Bosc) in southern Florida supports the contention by Hedgpeth (1953) that at least some, perhaps many, of the disjunct records may be a result of insufficient collecting in south Florida. The Carolina marsh clam has been assumed to be a typical disjunct species since it was described as such by van der Schalie (1933). It was not included in Marine Shells of Southwest Florida by Perry (1940) nor in Florida Marine Shells by Vilas and Vilas (1945). Abbott (1954) apparently knew of no southern Florida material, and recent examination of collections of this species in the E. S. National Museum provided no material south of New Smyrna on the east coast or Fort Myers on the west coast of Florida. Gunter and Hall (1963) found a breeding colony in the St. Lucie River estuary near Fort Pierce, Florida extending the range nearly 275 km farther south along the Florida east coast but gave no details on the size of the population. The initial discovery of a single valve of the Carolina marsh clam in extreme southern Florida was made by Tabb and Manning (1961) in deltaic muds at the mouth of the East River where it enters Whitewater Bay in Everglades National Park. Since 1962 sufficient discoveries have been made in Everglades National Park to prove the existence of a breeding population occupying two rather different but adjoining habitats over an extensive area of southern coastal marsh.

Behavior of Biomphalaria glabrata and of Other Snails in a Thermal Gradient

A thermal gradient (ca 12 to 38 C), established in a trough containing a shallow depth of water, was used to study the behavior of Biomphalaria glabrata (= Australorbis glabratus), Bulinus truncatus, and Lymnaea palustris under uniform conditions of light. Twenty snails were used per trial and 10 trials constituted each experiment; groups of control snails were observed under similar conditions except for the absence of the thermal gradient. The location of snails in the trough was recorded 45, 60, 75, and 90 min after the start of each trial. Regardless of the initial pattern of placement in the gradient, normal, well-fed B. glabrata (8 to 10 mm diam.) generally avoided both thermal extremes, tended to avoid most of the cooler region, and accumulated with greatest frequency in zones approximating 27 to 32 C. These responses to the gradient were substantially unaltered when B. glabrata harbored immature or mature infections with Schistosoma mansoni, when large snails (15 to 19 mm) were used, or when near-total darkness was superimposed. However, well-fed B. glabrata congregated on wheat germ or lettuce when these foods were placed in a cool zone normally avoided by the snails. In the absence of food, B. glabrata which were starved prior to study, or which were well-fed but only 3 to 5 mm diam, became rather uniformly distributed in the gradient. Adult B. glabrata, L. palustris, and B. truncatus differed in their distributional responses to the thermal gradient; thus, B. glabrata were generally found in moderately warm loci, L. palustris tended to accumulate in the relatively cool portions of the gradient, and B. truncatus distributed themselves fairly uniformly throughout the gradient. The general findings may contribute to a better understanding of some of the influences underlying the localization of discontinuity of natural colonies of snails. Many aspects of the biology of normal and of trematode-infected snails are influenced by temperature. In most studies involving this parameter, snails have been confined at specified temperatures under conditions which precluded avoidance or escape. The following experiments were done to explore the behavior of Biomphalaria glabrata (= Australorbis glabratus), and of other snails, free to range in a thermal gradient. MATERIALS AND METHODS General Experiments were done in a temperature-controlled room (25 to 27 C) from which natural light was excluded. A bank of ceiling-level fluorescent lights, paralleling the long axis of the trough described below, provided an illumination of 50 to 60 foot candles at the surface of the trough. Snails used in most experiments were derived from the PR-2' strain of Puerto Rican B. glabrata maintained at 25 to 27 C on romaine lettuce. This strain originated in 1959 from one snail of the PR-2 strain (Pan, 1965). Except as noted, snails were 8 to 10 mm in diameter and were well supplied with lettuce until used. Different groups of snails were studied in successive sets of trials; some of the snails were reused on occasion, but only Received for publication 13 September 1967. * These studies were supported in part by Research Grant AI-00513 and by a Research Career Award from the NIAID, U. S. Public Health Service. after several days of normal maintenance had intervened. Certain experiments involved B. glabrata which had been infected, when small, by mass-exposure to miracidia of a Puerto Rican strain of Schistosoma mansoni (Chernin and Dunavan, 1962). In other experiments two additional species of snail were studied: Lymnaea palustris, 30 to 35 mm in length, maintained in this laboratory since 1958 (Michelson, 1961a); and Bulinus truncatus (? Liberia), 9 to 11 mm in length, maintained here since their receipt from Dr. Henry van der Schalie in 1963. These snails were liberally supplied with lettuce until used in experiments. Experimental conditions The temperature gradient was produced in a rectangular trough (88 by 10 by 7 cm) made of clear plastic (1/4 inch, Acrylite?). The trough (Fig. 1) was level and supported by rubber pads on a work bench. White blotting paper beneath the trough provided a uniform background. The central 70 cm of the trough was divided transversely into 14 numbered zones by parallel lines ruled 5 cm apart on the underside. Each end of the ruled area within the trough was bounded by a vertical stainless-steel screen (16-mesh per inch, 0.018 gauge wire) set transversely. In the space beyond each screen, a coil of 1/-inch aluminum tubing extended horizontally from wall to wall and rested on the floor of the trough. A circulating pump and lengths of rubber tubing conveyed hot water from a constant temperature bath through the coil set beyond zone 14; cold water was circulated through the opposite coil from an ice-water bath or from a refrigerated-heated bath and circulator (model 2093, Forma Scientific, Marietta, Ohio).

Preliminary Studies on Fasciolopsis buski (Lankester, 1857) (Giant Asian Intestinal Fluke) in the United States

Preliminary Studies on Fasciolopsis buski (Lankester, 1857) (Giant Asian Intestinal Fluke) in the United States

Recent Eupera (Pelecypoda; Sphaeriidae) in the United States

The taxonomic history of the sphaeriid clam genus Eupera is reviewed, and the morphological relationships of Eupera to other genera are examined. The presence of separate siphons, byssal threads, and the unusual marsupial development of the embryos require the establishment of a new subfamily, Euperinae. Eupera singleyi (Pilsbry) is synonymized under E. cubensis (Prime) which is redescribed in detail. The specific distribution of E. cubensis, the single Recent member of the genus in the Nearctic Region, is in the Atlantic and Gulf 'Coastal Plains from North Carolina to Mexico, and the Valley and Ridge Province in central Alabama. IN1TRODUCTION Most published information on the ovoviviparous and hermaphroditic freshwater clam family Sphaeriidae concerns the taxonomy, life history, and distribution of the genera Sphaerium Scopoli, Musculium Link (frequently considered congeneric with, or a subgenus of, Sphaerium), and Pisidium C. Pfeiffer. Aside from the original descriptions, little is known of the highly localized monotypic genera Byssanodonta d'Orbigny (Rio Parana, Provinz Corrientes, Argentina) and Pseudocorbicula Dautzenberg (Lake Victoria, Kenya). Eupera Bourguignat is widespread in the Ethiopian and Neotropical Regions with one species, E. cubensis (Prime), occurring in North America. The present report is concerned with the systematics and distribution of E. cubensis in the Nearctic Region. The life history and anatomy of this species will serve as the subject of a later report. I am indebted to F. G. Thompson of the University of Miami Department of Zoology, J. C. Dickinson of the Florida State Museum, H. Rehder and J. P. E. Morrison of the U.S. National Museum, and H. van der Schalie of the University of Michigan Museum of Zoology for their kindnesses in providing material for examination. Special appreciation is extended to W. J. Clench of Harvard's Museum of Comparative Zoology (MCZ) and to R. T. Abbott of the Academy of Natural Sciences of Philadelphia (ANSP) for the loan of Prime's cotypes of Sphaerium cubense and Pilsbry's holotype and paratypes of Sphaerium (Limosina) singleyi, respectively. TAXONOMIC HISTORY Bourguignat (1854a) divided Pisidium C. Pfeiffer (1821) into two large series (subgenera?): (1) Pera Leach (1852) in which the ligament is on the shortest side of the beaks, and (2) Eupera I This investigation was supported (in part) by research grant 5 TI AI 41-05 from the National Institute of Allergy and Infectious Diseases, U.S. Public Health Service.

Studies on Puerto Rican Physidae

MEMBERS of the family Physidae a-re among the most ;common and widespread fresh-water mollusks in Puerto Rico and are frequently associated with Au8stralorbis glabratus, intermediate sna,il host of Schistosoma imansoni. In several recent papers on the ecology of A. glabratu,s in Puerto Rico (1-4) and in a key to the fresh-water mollusks of Puerto Rico by Van der Schalie (5), the only physid referred to is Phy&a cubensis Pfeiffer. Ferguson and Richa,rds (6) reviewed listings of phys,id mollusks from Puerto Rico by earlier collectors (including severa,l species of Physa and Aplexa), confirming P. cubensis and adding Aplexa marmorata (Guilding) from recent collections. As a potential intermediate host of Fasciola hepatica, P. cubensis (7) must be differentiated from Aplexa if molluscacidal control of sheep liver fluke disease, is attempted locally.

Reproductive Isolation in the Snails, Pomatiopsis Lapidaria and P. Cincinnatiensis

Even though their ranges overlap, two species of the American snail Pomatiopsis are usually ecologically isolated, with Pomatiopsis lapidaria (Say) inhabiting seepage areas and P. cincinnati- ensis (Lea) occurring only on river banks. A site was found on the River Raisin in Michigan where both species occurred together. Inten- sive studies over an extended period indicated that these species do not interbreed under natural, sympatric conditions. Previous to World War II, when the interest in human blood fluke was revived, Bartsch (1936) had grouped the Oriental snails which serve as intermediate hosts of Schistosoma japonicum under three gen- era: Katayama, Schistosomophora and Oncomelania. These are now all included in the single genus Oncomelania (Abbott, 1948). The status of the four species (0. quadrasi, 0. nosophora, 0. formo- sana, and 0. hupensis) within this genus is now also open to question. In this connection, Pesigan and co-workers (unpublished data) were able to intercross three species (0. quadrasi, 0. nosophora and 0. for- mosana) in any combination. These crosses were later confirmed by Wagner and Chi Wong (1959); in addition, they were able to cross 0. hupensis with the other three species. The hybrids of all these On- comelania crosses produced fertile offspring. Furthermore, it has been possible to cross males of the North American species, Pomatiopsis lapidaria, with females of Oncomelania quadrasi and 0. formosana (van der Schalie, et al., in press). The offspring of at least the former cross proved to be fertile. Attempted crosses of another North Ameri- can species, Pomatiopsis cincinnatiensis, with the four species of On- comelania and P. lapidaria were all unsuccessful. All of the nominal species of Oncomelania are allopatric. The tax- onomic status ascribed to, them depends on the definition of a species when dealing with allopatric populations. Judgments regarding the relationship between Oncomelania and Pomatiopsis also involve groups widely separated in nature. Although the ranges of P. lapidaria and P. cincinnatiensis overlap throughout an extensive area (van der Schalie and Dundee, 1955; Dundee, 1957), these species are usually ecological- ly isolated. Studies over an extended period indicate that P. cincin- natiensis occurs only on the banks of rivers, while P. lapidaria normally lives in seepage areas in the vicinity of streams and lakes. However, the latter species may occasionally appear on river banks (probably in

The Impact of Impoundment on the Mussel Fauna of Kentucky Reservoir, Tennessee River

Collections made in Kentucky Reservoir during 1958 indicate that the pre-impoundment assemblage of species, characterized by a preponderance of species belonging to the Unioninae, is doomed; only Quadrula quadrula has adapted to the altered ecological conditions. This species along with two species of Leptodea, one species of Carunculina, and three species of Anodonta comprise the dominant species assemblage in post-impoundment habitats. The impoundment of the waters of the Tennessee River by the TVA has produced a radically altered environment for the survival of the native mussel fauna. The singularly rich pre-impoundment mussel fauna of this area consisted almost exclusively of typical large river forms, many of which are of considerable commercial value; the pigtoe (Pleurobema cordatum) and the niggerhead (Fusconaia ebenus) are the two most abundant commercial species. Present concern for the future of this mussel fauna is evidenced by the 1956-57 study of this resource undertaken by the U. S. Fish and Wildlife Service (Scruggs, 1960). Scruggs' study adequately summarizes the present status of the native pre-impoundment fauna occurring above the area considered here but does not record any mussel invasion of the extensive mud shallows which have resulted from impoundment. Ecologically, the invasion of these virgin shallows is of prime interest and is the subject of this report. Grateful acknowledgment is due Dr. Henry van der Schalie, Museum of Zoology, The University of Michigan, and Dr. Ruth Patrick, Department of Limnology, The Academy of Natural Sciences of Philadelphia, for their generous help and criticism in the preparation of this paper. During October, 1958, sampling was completed over approximately sixteen river miles.2 On TVA Navigation Charts, this area extends from mile 88 to mile 105 and includes the entrance of Duck River. This region is from 4 miles above to 12 miles below Ithe U.S. Route 70 bridge at New Johnsonville, Tennessee. The deep water collections for adult mussels were made with a small crowfoot brail operated by a local clammer. A Peterson dredge was used to, obtain juveniles. In the shallows, hand picking, pollywogging, raking, and screening were employed. The Kentucky Reservoir in the area studied presents three main types of habitats suitable for mussel populations. The first is the old river channel with its firm sand and gravel substrate which gradually is being covered with a deposit of silt; the second is the extensive mud 1 Present address: 1900 Dexter Avenue, Ann Arbor, Michigan. 2 These collections were made under the auspices of the Limnology Department, The Academy of Natural Sciences of Philadelphia.

A Method for the Relaxation and Immobilization of Pulmonate Snails

In studies on the biological control of schistosome-bearing snails, the inoculation of microorganisms into pulmonate snails proved to be exceedingly difficult. Methods available for relaxing mollusks were ineffective. Most of the chemical agents recommended in the past for relaxing mollusks, including chloral hydrate, cocaine, carbon dioxide, chlorotone, nembutal, and aqueous and alcoholic solutions of menthol (Berry, 1943; Hubendick, 1954; Lee, 1950; van der Schalie, 1954), were intended primarily to facilitate killing, fixing, and to provide specimens for dissection. Our snails rarely recovered after being exposed to concentrations required for adequate relaxation. It has been our experience that prolonged exposure to certain of these chemical agents, as required for adequate relaxation, disturbed the osmo-regulatory mechanism of the snail's tissues, permitting an increase of hemolymph in the foot and neck sinuses resulting in swelling of these regions. Injection into these distended regions often resulted in profuse hemorrhage. In the present study a method was developed which results in complete exposure of the anterior portion of the snail's body and in preventing its subsequent retraction until inoculation is completed. Two inherent difficulties associated with inoculating snails, (1) the intense withdrawal reaction to tactile and chemical stimuli and (2) the lack of resistance offered by their tissues to positive pressure, are successfully controlled. The technique is a two-step procedure incorporating both chemical and mechanical action. In the first step, the snail is partially narcotized to facilitate subsequent mechanical extension and immobilization. Narcotization is accomplished by immersing the snail in a 0.5 to 1.0 percent aqueous solution of urethan2 (ethyl carbamate). The concentration of urethan and the interval of exposure are dependent upon the species and size of the snail. We have found that a concentration of 0.5 percent urethan and an exposure of three to five hours were suitable for Australorbis glabratus and Helisoma anceps having a shell diameter of 10.5 to 15.5 mm. Australorbis having a shell diameter greater than 16.0 mm. were kept overnight (15-18 hrs.) in a 0.5 percent solution. In a series of experiments (Table 1) it was observed that Australorbis would recover from exposures of 48 hours at concentrations of 0.5 percent urethan. A proper degree of narcotization generally results in the protrusion of the preputium.

A Kansas Pleistocene Herpetofauna

THE following report is based on specimens collected by field parties of the University of Michigan Museum of Vertebrate Paleontology (UMMVP), under the direction of Dr. Claud W. Hibbard, during the summers of 1947, 1951 and 1952, these specimens are now contained in the collection of that institution. They were recovered from a deposit in the Kingsdown Formation (considered a local unit of the Sanborn Formation by Frye and Leonard, 1952) of Meade County, Kansas. The fauna of this deposit has been termed the Jinglebob Fauna by Hibbard (1953). As indicated by van der Schalie (1953), this fauna is tentatively correlated with the Sangamon interglacial. The invertebrates have been discussed by van der Schalie (op. cit.), certain mammalian elements of the fauna were described by Rinker (1949), and Oelrich (1953) has described a new species of Terrapene. I wish to express my gratitude to Dr. Hibbard for the opportunity to examine these specimens and prepare this report thereon, and for other assistance he has provided during the course of this study. I also wish to thank Dr. Edward H. Taylor, of the University of Kansas Natural History Museum, for permission to examine comparative skeletal material in the collection of that institution and in his personal collection, and for the many helpful suggestions and other assistance he has offered.