Invertebrate Cave Fauna 
21 
Fig. 7. Distribution of aquatic cavernicolous snails ( Fontigens ) in the study 
area. Spring localities for F. orolibas in the Blue Ridge Mountains not shown. 
F. nickliniana, an epigean species previously recorded from a number 
of localities in the eastern United States. However, the recent study of a 
population in Unthanks Cave, utilizing internal anatomy in combination 
with shell morphology, suggests that one or more undescribed troglobitic 
species inhabit caves of the Powell Valley (R. Hershler and F. G. 
Thompson, in litt.). Another population in need of additional taxonomic 
study and clarification is one from Skyline Caverns tentatively identified 
by Morrison (1949, pers. comm.) as an undescribed species of the 
European subterranean genus Lartetia. Morrison (1949, pers. comm.) 
has taken a different view from that of Hubricht and believes that 
Fontigens in the Appalachians represents a complex of closely similar 
genera composed collectively of many well-isolated troglobites. Un- 
fortunately, his observations are mostly unpublished and thus unavailable 
for biogeographic analysis. 
Terrestrial cave snails were usually collected from damp, rotting 
wood; only a few populations were noted. Seven species in three 
families have been recorded to date. Helicodiscus notius specus 
(Helicodiscidae), a “somewhat degenerate form” (see Barr 1967a) of the 
widespread, primarily epigean H. notius (Hubricht 1962) was originally 
