1914 ] S. Kemp : Notes on Crustacea Decapoda. 113 



Indian Museum. One of these, H. ensirostris, a peculiar form 

 which shows but little affinity with anj^ species hitherto known, 

 is remarkable for its wide range of variation. It seems, indeed, 

 that extensive variation exists throughout the genus in regard to 

 the rostral armature, the proportional length of the legs and the 

 number of segments in the carpus of the second pair ; in 

 consequence it is not advisable to found species on these characters 

 alone. In the case of the Indian species the armature of the 

 dactylus of the last three peraeopods, the development of the 

 epipods and of the antero-lateral spine of the carapace and the 

 form of the telson have proved of considerable value in systematic 

 work. The colouration of at least some of the species is very 

 striking and it is probable that they could be more easily recog- 

 nized in the field than from preserved material. 



The Indian species of Hippolysmata may be determined b}'' 

 the following characters : — 



I. Rostrum shorter than carapace, without elevated basal 



crest ; pterygostomian spine, if present, smaller than 

 antennal : lateral margins of telson convex, apex blunt 

 with a pair of spines. 



A. Rostrum not reaching beyond second segment of an- 



tennular peduncle, inferior margin with 2-4 teeth ; 

 dactylus of last three peraeopods terminating in two 

 large claw-like spines. 



1. A minute spine at antero-lateral angle of carapace ; 



fingers of first peraeopods, when closed, meeting only 

 at tips. 



a. Second peraeopods symmetrical, carpus composed 



of 15-24 segments ... ... ... .. H. vittata. 



b. Second peraeopods asymmetrical, carpus composed 



of 28-32 segments. ... .. ... ... H. vittata, var. 



2. No spine at antero-lateral angle of carapace ; fingers 

 of first peraeopod, when closed, meeting throughout 



their length. .. ... ... ... ... H. kiikenthali. 



B. Rostrum reaching beyond antennular peduncle, inferior 



margin armed with 6-7 spines ; dactylus of last three 

 peraeopods simple. ... ... ... ... H. dentata. 



II. Rostrum longer, usually very much longer than carapace, 



with an elevated dentate basal crest ; pterygostomian spine 

 as large as antennal ; lateral margins of telson concave, 

 apex acute and unarmed. 



A. Carapace smooth or sparsely punctate laterally, depres- 



sion between branchial and cardiac regions usually 

 obscure; basal crest of rostrum with 7-12 teeth ; fifth 

 peraeopods not extending beyond antennal scale. ... H. ensirostris. 



B. Carapace coarselv and closely punctate laterally, depres- 



sion between branchial and cardiac regions distinct ; 

 basal crest of rostrum with 4-8 teeth ; fifth peraeopods 

 extending beyond antennal scale by at least length of 

 dactylus. ... ... ... ... ... do, \ar. punctata. 



Hippolysmata vittata, Stimpson. 

 Plate VI, figs. 6—10. 



1901. Hippolysmata vittdta, Lanchester, Proc. Zool.Soc, London, p. 563. 



1906. Hippolysviata vittata, Nobili, Ann. Sci. nat. Zool. (9), IV, p. 46. 



1907. Hippolysmata vittata, de Man, Trans. Linn. Soc, Zool. (2), IX, 



p. 423, pi. xxxiii, figs. 49, 50. 



