Indian Deep-sea Crustacea. 283 



From P. propensalata it differs in having seven carinas on 

 the carapace instead of five, and in the far more elaborate 

 sculpture of the abdominal terga, as well as in the greater 

 obliquity of the antero-lateral angles of the carapace. 



Four specimens from the Andamans, 55 fathoms. 



Family Alpheidae. 



Alpheus, Fabr. 



Alpheus Shearmu, sp. n. 



This species in the frontal region of its carapace resembles 

 Alpheus tridentatus, Dana, while the hand of its right chela 

 resembles that of Alpheus gracilipes, Stimpson. 



The integument is thin and submembranous. 



The carapace is perfectly smooth, rounded and non-carinate 

 superiorly ; the rostral and supraocular teeth are subequal 

 and very short ; the eyes are somewhat deficient in pigment 

 and so small that they cause no projection upwards of the 

 carapace. 



Near each postero-lateral angle of the telson is a couple of 

 small spines and on each side of the dorsal surface of the 

 telson is a similar couple of spines. 



The telson and plates of the swimmeret are fringed with 

 long hair. 



Of the antennulary base the first joint is slightly longer 

 than the second and the latter about twice the length of the 

 third. The antennulary acicle is flat and tapers quickly from 

 its base to a slender sharp needle-like point reaching about 

 one third the way along the second joint. 



The antennal scale is wide, thin and convexly curved in 

 its anterior and inner margins, thickened and slightly con- 

 cave as to its outer margin, which terminates in a short sharp 

 tooth. 



The right great chela, the only one present, is twisted so 

 that the finger and thumb lie horizontally. The lower and 

 inner margin of the hand is quite smooth and continuous with 

 the thumb, the outer and upper margin presents a V-shaped 

 notch close to the articulation of the hand and finger. 

 Running from end to end of the upper surface of the hand, 

 close to its outer margin, is a groove with a well-marked 

 rounded crest on its inner side. The distal end of the crest 

 ends on a level with the notch on the upper margin in a some- 

 what prominent smoothly rounded eminence. 



The opposable edge of the thumb is slightly curved and 



