24 U.S. NATIONAL MUSEUM BULLETIN 292 



Ortmann, 1913; Hobbs and Villalobos, 1964; and Hobbs, 1967). Its 

 closest relative, P. cuhensis rivalis, is found, as might be expected, 

 in western Cuba, where its range is limited to a small area in the 

 mountainous portion of Provincia de Pinar del Rio. The more ad- 

 vanced P. c. cuhensis is widespread in Cuba and is also present on 

 Isla de Pinos, and the troglobitic P. niveus is known from a single 

 cave in the westernmost province on the island. 



It is suggested that the invading stock, presently best represented 

 by P. atkinsoni, reached Isla de Pinos in the late Miocene or Pliocene 

 and that soon thereafter it reached the nearby Cuban coast. Once 

 on Cuba, one portion of the stock retained the primitive facies, 

 occupying moderately to swdftly flowing streams, and is represented 

 today by P. c. rivalis. The other portion moved into sluggish streams 

 and eventually into lentic habitats and, in adapting to such, was 

 able to spread throughout the island. This stock gave rise to P. c. 

 cuhensis, which subsequently spread to the ancestral home on Isla 

 de Pinos, passively to be sure, but as to whether or not it was in- 

 troduced by man will probably never be known. Procambarus niveus 

 was probably derived from the stock of P. c rivalis, a population 

 that invaded subterranean waters of western Cuba, probably in the 

 late Pliocene or early Pleistocene. 



The Pseudothelphusidae: The pseudothelphusid fauna of the West 

 Indies is composed of thi-ee genera: EpUohocera represented by six 

 species, Guinotia by two, and Pseudothel'phusa by three. 



The Antillean endemic genus EpUohocera is confined to the Greater 

 Antilles and Saint Croix, \\dth four species {E. armata, E. cuhensis, 

 E. gertraudae, and E. gilmanii) on Cuba, one {E. haytensis) on His- 

 paniola, and one (E. sinuatifrons) on Puerto Rico and Saint Croix. The 

 apparently more primitive species, E. gilmanii and E. cuhensis, occur 

 respectively on Isla de Pinos and on Cuba. The slightly more ad- 

 vanced E. armata, which has been reported from Provincia de Las 

 Villas, tends to link the primitive Cuban species with the more 

 specialized E. haytensis and E. sinuatifrons. Differing from both 

 groups is E. gertraudae, which apparently frequents subterranean 

 waters in the western portion of Cuba. 



EpUohocera is probably the most primitive of the Antillean pseudo- 

 thelphusids, possessing a well-developed exopod on the third max- 

 illipeds and having a comparatively simple first pleopod in the males 

 that is remarkably similar in aU the species. Its absence from the 

 Lesser Antilles suggests a Central American-Mexican origin rather 

 than a South American one, and, inasmuch as it has undergone a 

 greater degree of diversity than the other pseudothelphusids in the 

 Antilles, it seems likely that the ancestral stock reached the Greater 

 Antilles earlier, possibly Miocene or early Pliocene, than did the 



