208 Dr. A. Alcock on a new 



record another new species, from Cacliw, bringing up the 

 nnmber of Indian species to 6. 



The Indian CseciHans liitlierto known belong to three 

 genera, of which one, IcJithyopliis, is found only in the 

 Oriental region ; another, Gegenophis, is peculiar to the 

 S'Utheru end of the Indian peninsula; while the third, 

 Ura'ofyphhts, is represented in Southern India (Malabar) 

 and in West Africa just north of the Equator (Gaboon). 



The new Indian species, which comes from the district of 

 Cachar in the province of Assam, belongs to a genus, 

 Ilerpele, of which three other species are known, namely, 

 II. ochrocfphaJa, Cope, from Panama, and IJ. squahstoma 

 (Stuchbury) and H. Bornmuelleri^ Werner, from West 

 Africa (Gaboon and Seneganibia). 



The range of this genus Ilerpele, which touches practically 

 all the salient strongholds of the order to which it belongs, 

 seems striking enough to require some special explanation, 

 for it can hardly be sup;)Osed that the immediate ancestors 

 of a form that is modified for underground life and guards its 

 eggs in its burrows could, even though its larvre live for a 

 time in fresh water, be transported through 170° of meridian 

 and across great oceans solely by those distributing agencies 

 that are recognized by zoologists who maintain that continents 

 and oceans are permanent. 



§ 2. The Distribution of the Cmciliidm compared with 

 • THAT of certain Svblittobal Genera of Hermit- 

 crabs. 



It has occurred to me that some light is thrown upon the 

 case of IJerpeh and upon the distribution of the Ca?ciliidai in 

 general by the geographical affinities of certain elements of 

 the sublittoral fauna of the seas of India. 



I am of course aware that ordinary marine animals, both 

 as adults and even more in their larval stages, are supposed 

 to live under simpler conditions and to be less restrained by 

 physical barriers than land animals. Without arguing that 

 question, I may, perhaps, minimize the force of this objection 

 by selecting the sublittoral hermit-crabs (Paguridse), very 

 few of which have even the most moderate swimming-powers, 

 and a good many of which — as we may conclude from the 

 comparative large size and fewness of their eggs — do not 

 periodically squander a multitude of unspecialized larvae 

 abroad. 



I have lately completed a sort of monograph of the 

 Paguridse, and I find that the species inhabiting the sub- 



