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Greaser (1934), Mackin (1935), and Shoemaker (1938, 1942a, 1942b, 1945) 1893; Stebbing, 1906;Banta, 1907;Weckel, 1907;Holmes, 1909, Stout, 1911, but none of these added any further data to those given initially by Smith. Only one other stygonectid was described before the tm-n of the century, this being Crangonyx flagellatus (Benedict, 1896) Both Spandl (1926) and Chappuis (1927) Mackin (1935) added further to this confusion by describing another new stygonectid amphipod from Oklahoma and assigning it to the otherwise monotypic, European genus Boruta (B. americana Mackin, 1935). Shortly after this, however, Boruta was synonymized with Synurella (Schellenberg, 1936). While Mackin (1935) Dearolf (1937, 1941, 1948,1953) Holsinger, 1963Holsinger, , 1964Nicholas, 1960; (Stone, 1953), Vbginia (Douglas, 1964), West Virginia (Davies, 1958, 1965, Missouri (Bretz, 1956), Maryland (Davies, 1950), and Texas (Craun, 1948;White, 1948 The term "syn topic" as defined and discussed by Rivas (1964) has been adopted and given rather extensive application in this paper.Since "syntopic" is a relatively new and still poorly known term, its definition will be repeated here as given by Rivas (1964, p. (Hynes, 1955). Hynes has further pointed out that in some gammarids the brood plates acquire serrated edges at the last molt before maturity. Although his observations were based on epigean species, they apparently have direct apphcation to the material at hand. In the present study sexually mature females of different sizes were often noted in samples, but appreciable differences in meristic characters between smaller and larger specimens were not usually apparent, despite the fact that growth undoubtedly continued after sexual maturity was initially attained. At most, larger, sexually mature females had only a few more spines and setae than smaller ones.In view of these observations it was generally assumed through- In only a few instances was it necessary to base descriptions or diagnostic characters on what appeared to be slightly immature specimens, and where such action was necessitated, it is so indicated.Ideally, where this has occurred, future collecting will provide sexually mature specimens of these species, at which time their diagnostic characters can be reevaluated and brought into fine with those species in the genus described from mature individuals.

Holsinger, John R., and Glenn Longley. The Subterranean Amphipod Crustacean Fauna of an Artesian Well in Texas. Smithsonian Contributions to Zoology, number 308, 62 pages, 27 figures, 1980.-Subterranean amphipod crustaceans of the suborder Gammaridea have been sampled on a regular basis from the artesian well in San Marcos, Texas, since late 1973. Water in the artesian well comes from the extensive, subterranean Edwards Aquifer, which is associated with the Balcones Escarpment and Fault Zone of south-central Texas. The taxonomically diverse amphipod fauna of the well is believed to be one of the richest of its kind in the world and is composed of five families, six genera, and 10 species. One family, four genera, and six species are newly described herein. Four distinct phylogenetic lineages are represented in the amphipod fauna: crangonyctids, hadzioids, bogidielloids, and sebids. The zoogeographic and ecological implications of the artesian well amphipod fauna are profound. Approximately 80 jiercent of the species have obvious affinities with marine or brackish water species and are presumably derivatives of marine ancestors that colonized newly opened freshwater habitats during recession of epeiric seas in the Late Cretaceous. The high taxonomic diversity of the amphipod fauna is probably explained by: (1) exposure of south-central Texas to an extensive marine embayment during the Cretaceous period, (2) complex geological structure of the Balcones Fault Zone and large size of the Edwards Aquifer, and (3) ecological complexity of aquatic communities in the Edwards Aquifer. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report. Smithsonian Year. SERIES COVER DESIGN: The coral Montastrea cavernosa (Linnaeus). Library of Congress Cataloging in Publication Data Holsinger, John R. The subterranean amphipod crustacean fauna of an artesian well in Texas. (Smithsonian contributions to zoology ; no. 308) Bibliography: p.

The comparative data from studies of two 'superfamily' groups with large numbers of subterranean taxa, the exclusively freshwater Crangonyctoidea and the predominately marine Hadzioidea, support the hypothesis that distributional patterns and evolutionary processes of stygobiont amphipods are closely linked and that the former can be a useful indicator of the latter. Three major biogeographic patterns are indicated by the distribution of subterranean species in these groups, each apparently reflecting a particular mode of origin: (1) freshwater stygobionts (limnostygobionts) derived from epigean freshwater ancestors through colonizations probably influenced by adaptive shifts, or assisted by stream capture and spring failure; (2) freshwater stygobionts derived from marinelbrackish water ancestors by stranding during regression of marine embayments; and (3) marinebrackish water stygobionts (thalassostygobionts) derived from epigean marinebrackish water ancestors through adaptive shifts possibly in concert with fluctuating sea levels. ZusammenfassungVergleichende Untersuchungen zweier Superfamilien, jede mit einer grossen Anzahl unterirdischer Taxa, die ausschiesslich im Susswasser verbreiteten Crangonyctoidea und die vorwiegend marinen Hadzioidea, stutzen die Hypothese, dass Verbreitungsmuster und phylogenetische Prozesse stygobionter Amphipoden eng miteinander verbunden sind, und dass Erstere ein niitzlicher Indikator fur Letztere sind. Die Verbreitung unterirdischer Arten in dieser Gruppe weist auf drei biogeographische Muster hin, von denen jedes eine bestimmte Herkunft reflecktiert: (1) Susswasser-Stygobionten (Limnostygobionten) konnen durch Kolonisation, wahrscheinlich beeinflusst durch Veranderungen in der Anpassung, aus epigaischen Susswasser-Vorfahren hergeleitet werden, oder unterstutzt durch 'stream capture' und 'spring failure' (Versiegen von Quellen); (2) Susswasser-Stygobionten stammen von marinen1Brackwasser-Vorfahren ab, welche im Verlauf der marinen Regression 'gestrandet' sind: und (3) marine/Brackwasser-Stygobionten (Thalassostygobionten) enstammen epigaischen marinen/BrackwasserVorfahren durch Veranderungen in der Anpassung in Zusammenhang mit Wasserstandsanderungen.

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