Freshwater Crustacea of the Indian Archipelago. 249 



a species of Geophagus] Cirolana elongata, H. M.-Edw., in 



the mouth of the Ganges ; while Olencira prcegustator ^ 

 Latrobe, lives upon the coast of North America, but is found 

 besides in rivers in that region. With regard to Glossohiua 

 laticauda^ M.-Edw., it is stated by Schiodte and Meinert that 

 it is found in all warm seas upon species of Exocoetus, and 

 when we find the River Continguiba (Maroin) included 

 among the localities, we can only conclude that the authors 

 are here speaking of the mouth of the river, which is probably 

 the only portion sufficiently salt to enable Eococcetus still to 

 exist in it *. 



Now if we further consider that, besides numerous marine 

 species which are inexactly described, we have, especially 

 owing to the work of Schiodte, Meinert, and Hansen, a more 

 precise knowledge of over one hundred and eighty species of 

 Cymothoinge, we shall be obliged to regard this family as 

 genuinely marine, and from the statements and resumes given 

 above we may conclude that an immigration into fresh water 

 is partly in progress and partly, as in the case of the three 

 Indian species Ichthyoxenus JeUinghausiiy Rocinela ti/pus, 

 and Tachcea lacustris, already completed. 



In our list there also appear two genera nearly allied to the 

 genus BojyyruSy with at least seven species. Semper was the 

 iirst to announce the occurrence of Bopynis in the fresh water 

 of the Philippines. Thereupon Giard and Bonnier described 

 Prohopyrus ascendens and Palcegyge Borrei, two species which 

 were found living upon freshwater Palasmonids in the Indian 

 Archipelago — the former upon Palcemoii lar^ Fabr., and the 

 latter upon P. dispar. 



To these I am consequently able to add further forms 

 living upon other species of the genus PaJxemon. 



It is well known that the family Bopyrida? is thoroughly 

 marine. Our potamophilous species must therefore be immi- 

 grants into fresh water, and this at the same time implies the 

 assertion that the genus Palcernon has also penetrated from 



* It is true that J. v. Kennel (' Ai-beiten a. d. Zool. Institut zu Wiirz- 

 bm'g,' 1883, p. 276) mentions " a Crustacean belonging to the genus 

 ^ga " as having been found by himself in fresli water upon the island of 

 Trinidad ; but no indication whatever of the species is given, as is much 

 to be desired in this case, considering the very ambiguous use that is 

 made of the name ^(ja. Von Kennel states that the occiu-rence of ^f/a 

 in the fresh water of the Patau Islands had already been made known by 

 Semper, and this is also repeated by Simroth. In spite of much search, 

 I have not been able to tind the statement alluded to. In Semper's 

 ' Existenzbedingungen der Thiere ' (p. 102) a blind " Cymothoon " from 

 " slightly brackish water " is certainly figured, but the geuus to which it 

 belongs is not determined. 



