Dr. W. T. Calinnii on Munidopsis polymorplia. 217 



wliich the cave communicates with the sea, found tlierc an 

 environment suitable, at least in the absence of light, to its 

 habits. 



It is possible that this case may have some bearing on the 

 general question of the origin of the subterranean fauna. It 

 has been stated, more especially with regard to the Crustacea, 

 that the subterranean forms are allied, not to the surface- 

 living freshwater sj)ecies, but to marine and, in some cases, 

 deep-sea forms. 8ome of the cases formerly adduced in 

 support of this view have been disposed of by subserjuent 

 criticism *, but a few forms still remain which appear to be 

 distinctly of a marine type. Among these the Isopod 

 Crureyens, described by Prof. Chilton from wells in New 

 Zealand, belongs to an otherwise exclusively marine family, 

 the Antliurida-. The same may be said of Dr. Benedict's 

 Cirolanides f and the Cirolana cuhensis recently described 

 by Mr. Hay \, both belonging to the Cirolanidaj, wliilc in 

 some other cases an affinity with freshwater forms seems to 

 liave been assumed rather than demonstrated. Among the 

 other groups of subterranean animals the most striking case 

 in ])oint is that of the two fishes Lucifuga suhterraneus and 

 Strjijicola dentatus ^ found in caves in the island of Cuba, 

 to which Mr. Boulenger has kindly directed my attention. 

 Tiiese belong to the Brotulidie, a family which has no other 

 representatives in fresh water, the great majority of the 

 genera coming from deep water, although some are shallow- 

 water or shore fishes. Tlio nearest allies of the cave-(ishes 

 are stated to be the genera Brotula and Ogilbia from shallow 

 water and JJussozetus and Aphijoiias from 1000-2000 

 fathoms ||. 



In all these cases the cave-dwelling animals, though living 

 in fresh water, are probably descended from forms which 

 have penetrated into the reservoirs of subterranean water by 



of the abyssal plankton are sometimes brought to the surface by the 

 strong tidal currents in the neighbourhood of the Canaries (.SB. Akad. 

 Wiss. Berlin, lb89, (^) p. o50). 



♦ Cf. Chilton, " The Subterranean Crustacea of New Zealand," Trans. 

 Linn. Sue, I'nd ser. Zool. vi. (2) p. 255 (1894). 



t Proc. U.S. Nat. Mus. xviii. p. 015 (l^Ob). 



X Proc. U.S. Nat. Mus. xxvi. n. 4-'J0 ( 190;3). 



§ I'oey, ' Memorias sobre la llistoria Natural de la I-la do Cuba. . . .,' 

 ii. (^1850-1858) pp. ''Mik. 102, pis. ix. & x. ; and ' liepertoriu tisico-natural 

 de la lala de Cuba,' i. (1865-I86ii) p. 113 ; Gill, Proc. Acad. Philadelphia, 

 p. 252 (I8t«). 



II Sfje Lun<^, " The Ovarian Structure of the Blind Fishes Lua/fu^a und 

 Styfjicola^'' Biol. Bull. vi. p. 38 (PJOl). 



