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cavemicolous, it lacked the troglomorphic modificationsof the latter, being distinctly pigmented andhaving well developed eyes, a robust eye mound,and relatively short appendages. Of particular interestwere the sexually dimorphic structures; maleshaving both a trochanteral spur, an elongate processon the ventral surface of the fourth trochanter, and apostopercular process, a conical outgrowth just posteriorof the genital operculum (Fig. 2). Althoughsimilar, but smaller, spurs are known from both aNearctic (Sitalcina Banks) and Palearctic genus(Scotolemon Lucas), the postopercular process isunique, as is the combined presence of two dimorphicstructures, and was the first clear indication ofa derived character defining the genus.In addition to the topotypes of T. reddelli, thesecollections also included specimens from severalother caves along the Balcones Escarpment. All ofthese specimens were troglomorphically intermediatebetween the two species. For example, they lackedthe retina (unlike T. reddelli) but retained at least avestigial cornea (unlike T. mulaiki). On the basis ofsomatic characters these additional specimens wereassigned to the two species: the most troglomorphicto T. mulaiki, the others to T. reddelli.Continued sampling of the Texas cave fauna producedadditional specimens of Texella, spreading theknown distribution of the genus over much of theBalcones Escarpment (Mitchell and Reddell, 1971),but turned up no further species. The presence ofonly two species of Texella now seems incongruous.On the one hand, this region is extremely rich inother cavernicolous arachnids; for example, themany species of the spider genera NeoleptonetaBrignoli (Gertsch, 1974), Eidmanella Roewer(Gertsch, 1984), and Cicurina (Cicurella) Menge(Gertsch, 1992). Furthermore, the other knownphalangodid faunas of the Nearctic region are quitespeciose. An unusually rich fauna is known fromthe Californian region (Briggs, 1968; Briggs andHom, 1966, 1967; Briggs and Ubick, 1981, 1989;Ubick and Briggs, 1989) and the Appalachian fauna,Figs. 1-4.-Texel/a spp., lateral views: I, T. bifurcata (Briggs), male topotype; 2, T. spinoperca, new species, maleparatopotype; 3, T. mulaild Goodnight and Goodnight, male, Fern Cave; 4, T. mulaild Goodnight and Goodnight, female, FernCave.156