230 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxv. 



The figure of Olophonis americanus Saussure/ however, shows a 

 rather deep excavation of the carpal seg-ments, and if Dr. Ortman is 

 correct" in regarding this the same as Xlphocarls elongata., the dif- 

 ferences l)etween Palxiuonlaa and Xi^lMcarls are very slight indeed. 



This species is of especial interest, since it has been shown by Dr. 

 Ortman that the Atyidre are extremely archaic fresh-water crustaceans, 

 and that of them the genus Xiphocaris is the most primitive. In 

 former times the distribution of Xlj^hoearlft was probably far more 

 extensive than it is at the present. To-dav but three surviving spe- 

 cies are known to science, ''one from the fresh waters of the West 

 Indies, another from streams and pools in Indo-Malaysia, and a third 

 from the streams of New Zealand. " ^ The isolated species, Palxmonias 

 ganteri and Trogolocaris f<chm!df!^ which, as has been pointed out, may 

 prove to lie congeneric with Xip/ioearis, are species which have been 

 left behind in the limestone caverns when the main bod}" of their rela- 

 tives was swept to the south. 



It offers also another proof of the fact that we may look to the 

 limestone caverns of the world for man}' of the most valuable clues 

 to the relationships of our present surface fauna. There are doubt- 

 less man}" cases in which the extension of habitat to the sul)terranean 

 retreats has been quite recent; l)ut, in the main, cave-inhabiting animals 

 are of archaic types and date from a time when conditions were more 

 uniform, and consequently faunal differentiations were less marked 

 than at the present day. In support of this sttitement it will be suf- 

 ficient to mention the occurrence in Carniola of a subterranean species 

 of crayfish very similar to those occurring to-day in North America, 

 and quite different from those of Europe, and the more recent dis- 

 covery in Texas of Ti/p/ih/nolge, a genus of blind, cave-inhabiting 

 salamanders, which, so far as it is known, finds its nearest relatives in 

 Proteu-^ of Carniola. 



Family ASTACIDyE. 



CAMBARUS PELLUCIDUS ( Tellkampf) . 



The "blind crayfish of Maumioth (^ave," which is now known to 

 inhabit the subterranean water courses of a considerable portion of 

 Kentucky and Indiana, was collected and observed frequently wherever 

 conditions were favorable. The shallow margins of the "River Styx " 

 and the small pools in the passage to Koaring River afforded me abun- 

 dant opportunities to study this interesting species. It was no uncom- 

 mon thing to have several under observation at one time. 



When first oliserved they were usually on the bottom, resting 

 quietly with their legs and antennae fully extended. Unless they were 



^Mem. Soc. Phys. Hist. Nat. Geneve, XIV, Pt. 2, 1858, p. 472, pi. iv, iig. 31. 

 ^Proc. Acad. Nat. Sci. Phila., 1894, p. 400. 

 ■^Idem, p. 400. 



