I9I7] 



S. Kemp : Notes on Crustacea Decapoda. 



57 



The external maxillipedes do not reach quite so far forwards 

 as the third peraeopods and extend to, or a little beyond the apex 

 of the antennal scale. The terminal segment of the external 

 maxillipede differs from that of all the other species in being 

 divided into three sub-segments; of these the middle one is the 

 shortest and the last the longest (text-fig. 6). There is no tooth 

 on the inner margin of the basis of the third peraeopods. 



The third thoracic sternite of the female is altogether peculiar ; 

 it projects backwards from the base of the third legs in the form of 

 a large plate, posteriorly overlying the fourth sternite. It is slightly 

 depressed in the middle line, its lateral edges are posteriorly 

 convergent and its distal margin, which is free, and in consequence 

 easily visible in lateral view, is conspicuously emarginate (text- 

 fig. 3^). 



a< 



Fig. 7. — Outer uropod, with portion of external margin more highly magnified. 



a. Acetes indicus. c. Acetes insttlaris. 



b. Acetes erythraeus. d, Acetes japonicus. 



The large-hooked tooth found in A. indicus and A. erythraeus 

 between the bases of the first pleopods is replaced, as in A. 

 insularis, by a small pointed process. 



The internal lobe of the petasma is truncate at its proximal 

 end and scarcely at all expanded. The distal portion is bulbous 

 at the tip and set with numerous mmute booklets ; on its outer 

 side it bears a large process usually terminating in a long and 

 very fine point (text-fig. 4^). The length of this pointed process is 

 variable ; sometimes it reaches to the end of the lobe to which it is 

 attached, while occasionally it terminates abruptly with a blunted 

 apex. 



The sixth abdominal somite, in lateral view, is a little more 

 slender than in the other species, its length being usually twice its 

 greatest depth. 



