Boone, Crustacea, Cruise of "Alva," 1931 81 



Orissa and Ganjam, Dumrah River, Palk Strait, Bombay, Sand- 

 heads, Hooghly River; Hong Kong, Penang (Alcock) ; Penang, 

 Malay Straits (Boone) . 



Material examined: Two males, three adult females and 

 one young specimen, collected at Georgetown, Penang, Malay 

 Straits, November 13, 1931. 



Technical description : The rostrum arises at a point about 

 one-third of the carapace length from the frontal margin and 

 possesses a distinct double curvature, its proximal curve bearing 

 a crest of eight spines in addition to the epigastric spine and the 

 distal portion is styliform, much shorter than that of the related 

 species and scarcely reaches the tip of the antennular peduncle. 

 The lateral rostral carina arises a short distance posterior to the 

 epigastric spine and vanishes anteriorly below the third from 

 distal spine. The rostral formula in the present specimens is seven 

 spines and the apex dorsally on four specimens ; eight spines and 

 the apex dorsally on two specimens. In three specimens these spines 

 are distributed on the proximal two-thirds of the rostrum; on 

 the remaining specimens the last two spines are distributed on 

 the distal styliform curve of the rostrum. The rostrum is some- 

 what longer in the females than in the males of the same size, 

 which have the styliform process reduced. The rostrum length is 

 variable, extending variously to the base of the third peduncular 

 article of the antennulae, to the base of the flagellum, or for a slight 

 distance beyond this point. The postrostral carina arises just 

 anterior to the posterior margin of the carapace and is decidedly 

 canaliculate behind the epigastric spine, which is approximately 

 in line with the hepatic spine. The epigastric spine is weak at its 

 base and no larger than the rostral spines from the first of which 

 it is well separated. The margin between the teeth is ciliated. 

 The longitudinal suture of the carapace is a fine line arising be- 

 hind the orbit, continued some distance behind the gastric region, 

 extending three-fourths of the carapace length. On either side 

 of the carapace there is a long transverse suture line opposite the 

 base of the fourth pair of legs and extending upward halfway to 

 the median dorsal line ; in advance of this, about opposite the base 

 of the second pair of legs, there is a similar but shorter suture 

 line which is scarcely half so long as the posterior transverse line. 

 The orbital spine is definitely present, small, consisting of an acute 

 peak formed of the folded carapace and having a vei'y short post- 



