I9I7-] 



vS. Kemp : Notea on Crustacea Decapoda, 



45 



the shore in the open sea, and are frequently common in estuaries 

 and backwaters. They are often found where the water is of low 

 salinity, and occasionally in places where it is quite fresh, but 

 penetrate little if at all beyond the reach of tidal influence. The 

 species are fished commercially both in India and Japan, the small 

 size of the individuals being evidently compensated by the great 

 abundance in which they are taken. 



In life the greater part of the body is probably transparent in 

 ail the species, but the cornea is black, and in one species at least 

 there are red markings on the uropods. The precise distribution 

 of the red pigment is perhaps different in different species, but on 

 this point nothing precise is known. The only notes I possess on 

 the colouration of living examples relate to specimens of A. japoni- 

 ciis collected in Mormugao Bay in Portuguese India, my description 

 agreeing exactly with that given by Kishinouye. Dr. Annandale's 

 notes on individuals caught in the Tale Sap in Lower Siam indi- 

 cate an almost precisely similar colouration, but his collection 

 contains both A. indicus and A. japonicus, and it is not clear to 

 which of the two species the description refers. 



The four species may be recognised by the following charac- 

 ters : — 



I. Ciliated and non-ciliated portions of external border of 

 outer uropod separated by a small but distinct tooth ; 

 terminal seg-ment of 3rd maxillipede not di\'ided into 

 sub-segments ; 3rd thoracic sternite of female not pro- 

 duced backwards as a large plate. 

 A. Telson reaching beyond middle of inner uropod, 

 its apex pointed, without spinules ; a single 

 clasping spine on external antennular flagellum 

 of male. 



1. A tooth at distal end of inner margin of 



basis of 3rd peraeopods ; 2nd segment of 

 antennular peduncle fully three times as 

 long as broad ; petasma without mem- 

 branous coupling folds, its internal lobe 

 strongly expanded at its proximal end, 

 the distal portion terminating simply 



2. No tooth on basis of 3rd peraeopods; 2nd 



segment of antennular peduncle of female 

 not more than two and a half times as long 

 as broad ; petasma with a pair of folded 

 coupling membranes armed with hooks, 

 internal lobe little expanded proximally, 

 its distal portion terminating in two large 

 pointed processes 



indicus, Milne- 

 Edwards. 



erytJiraeiis, 



Nobili. 



B. Telson not reaching beyond middle of inner 

 uropod, its apex truncate with a spinule on either 

 side ; two clasping spines on external antennular 

 flagellum of male [petasma without membran- 

 ous coupling folds, its internal lobe very strongly 

 expanded and conspicuously emarginate proxi- 

 mally, the distal portion terminating simply] 



II. Ciliated and non-ciliated portions of external border 

 of outer uropod not separated by a tooth ; terminal 

 segment of 3rd maxillipede divided into three sub-seg- 



insitlaris, 

 sp. 



