2 1 CRUSTACEA CHAP. 



dwellers have been investigated especially at Carniola and in the 

 American caves. 



A number of species of Cyclopidae and Cypridae, many of 

 which are blind and colourless, have been brought up in well- 

 water. The Amphipod Niphargus puteanus has long been 

 known from a similar source in England : and all over Europe, 

 and several other blind Gammarids inhabit the subterranean 

 waters and caves in various parts of the world. Among 

 Isopods, Asellus cavaticus is recorded from wells and caves in 

 various parts of Europe, Caecidotea stygia and C. nickajackensis 

 from the Mammoth and Nickajack Caves in America, and two 

 very remarkable blind Isopods are described by Chilton from 

 the subterranean waters of New Zealand, viz. Cruregens fontanus, 

 whose nearest allies are the marine Anthuridae, and the Isopods 

 Phreatoicus typicus and P. assimilis,v?hich bear an extraordinary 

 resemblance superficially to Amphipocls. Besides these, a small 

 number of subterranean Decapoda are known which retain the 

 eye-stalks but are without functional ommatidia. These are 

 Troglocaris schmidtii, in Hungary, related to the fresh-\vater 

 Atyid Xiphocaris of East Indian and East Asiatic fresh waters 

 rather than to the South European Atyephyra ; Palaemonetes 

 antrorum, from artesian wells in Texas ; and several species of 

 Cambarus from the Eastern United States. A blind species of 

 Catnbarus, C. stygius, has been described from the caves of 

 Carniola, and if this determination is correct, is the sole Cambarus 

 occurring outside America. 



It will be seen from the above account that the sub- 

 terranean Crustacea are an exceedingly interesting and, in many 

 respects, archaic group, many of which have survived in these 

 isolated and probably uncompetitive districts, while many 

 secular changes were going on in the quick world overhead. 



The remaining fresh water Malacostraca may be mentioned 

 under the headings of the groups to which they belong. 



Only one " Schizopod," apart from Paranaspides, is known 

 from fresh-water lakes, viz. Mysis relicta, which was discovered in 

 1861 by Loven in the Scandinavian lakes, and has since been 

 found in the Finnish lakes, the Caspian Sea, Lake Michigan, and 

 other localities in N. America, and Lough Erne in Ireland. This 

 species is closely related to Mi/sis oculata of Greenlandic seas. 



1 S. F, Harmer, Trans. Norfolk and Norwich Nat. Soc. ii., 1899, p. 489. 



