On Tioo new Amphipods from the. West Indies. 397 



XLVI. — Tico new Amphipods from the West Indies. 

 By the Kev. Thomas R. R. Stebbing, M.A. 



[Plates XIV. & XV.] 



Amphithoe megalojirotopus, sp. n. 

 (Pis. XlV. and XV. B.) 



From Amphithoe, I.each, the genus Gruhia^ Czerniavski, is 

 separated only by its possession of a one-jointed accessory 

 flagellum on the upper antennae. From Microdeutopus, Costa, 

 Professor Delia Valle distinguishes Stimpsonella by the single 

 character that " the prehensile angle of the second gnathopods 

 in the male is prolonged into a more or less notable process." 

 Upon these precedents it is to be expected that the species 

 now to be described will not long escape from transfer to a 

 new generic name. It is, to be sure, a characteristic 

 Amphithoe, except in one respect; but, contrary to the 

 existing definition of that genus, it has the first gnathopods 

 larger instead of smaller than the second. Thus it is easily 

 distinguishable from all its hitherto known congeners, and at 

 the same time it shows an approximation between Boeck's 

 subfamilies of the Microdeutopinse and Amphithoinas, which 

 Delia Valle groups together with others in an extensive 

 family called Corophidge. 



The new species has the body flecked all over with stellate 

 markings, as is commonly the case in this genus. 



Ei/es placed on the front lobes of the head, rounded, of 

 moderate size, black in the specimen preserved in spirit. 



Upper Antennce. — First joint long and stout, fringed with 

 very long setae ; second joint much thinner, but not much 

 shorter than the first, with numerous tufts of setse ; third joint 

 short, slightly curved ; flagellum imperfect, the remnant as 

 long as the peduncle, containing twenty-three small joints. 



Lou- er Antennce. — Imperfect; the second and third joints 

 short and stout ; the fourth joint robust, nearly once and a 

 half the length of the first joint of the upper antennae. 



Mouth-organs. — As will be seen from the figures these are 

 of the usual type. This remark applies also to the second 

 maxillse, which were examined, but were accidentally lost 

 before they had been drawn. The left mandible has six 

 serrate spines in the spine-row, the right has only five ; the 

 secondary plate is stronglj^ denticulate on the left, but very 

 feebly on the right. The molar tubercle is partially fringed 

 with spine-like teeth and carries a long seta. The third 



