obtained in the Indian S^as. 239 



The rostrum narrows from the anterolateral teeth forwards ; 

 the antero-lateral teeth are large and prominent. The 

 anterior part of the third carina is represented by 3 or 4 

 very small discrete tubercles on the hepatic area. There are 

 a few scattered small low tubercles on the dorsum of the 

 carapace Ijctwcen the carinse. The large tubercles repre- 

 senting the first and second carinse and the broad flat low 

 tubercles of the abdomen have, like the other carinse of the 

 carapace, an eroded worm-eaten appearance. A fine velvety 

 l)ile covers the carapace and rostrum. 



There are only nine branchine on either side — arthro- 

 branchiffi (5) on ninth to thirteenth somites, and plenro- 

 branchise (4) on eleventh to lourteeutb — each series diminishing 

 in size from behind forwards. From its reduced number of 

 branchiae, its relatively small eyes, which are somewhat 

 deficient in pigment, and its dorsal and subdorsal carinas of 

 tiie carapace being broken up into lines of tubercles, this 

 Indian species would come under Alcock's subgenus Plasto- 

 cranyon (Alcock, Desc. Cat. Ind. Deep-sea Crust. 1901, 

 pp. 125 & 13o). 



Of Indian species already known it is most neai'ly related 

 to G. [Plastocrangon) ccecescens, from which it differs in 

 having larger eyes ; rostrum longer, slender throughout, 

 acute, and with only two pairs of teeth; a less granular 

 surface ; and only one tooth on the anterior part of the fourth 

 carina. G. sicaria (Faxon) differs from this species in 

 having the orbital spines smaller and less deflected, outwards 

 and the anterior part of the fourth carina divided by a 

 notch into two prominences, of which the posterior is 

 the more salient. In G. nobilis (A. j\I.-Edwards) the 

 rostrum is relatively shorter and its median dorsal keel 

 does not run so far back ; the 3 or 4 tubercles representing 

 the anterior part of tlie second (subdorsal) carina are all 

 produced to spinous points, and not merely the foremost of 

 them ; the tubercles on the abdomen are more numerous 

 and discrete ; the eyes have more pigment. 



Fam. Axiidse. 

 Calastacus, Faxon. 



Calastacus longispinis, McArdle. 



Calastacus lojif/ispinis, McArdle, Ann. & Mag. Nat. Hist. ser. 7, vul. viii. 

 Dec. 1901, p. 622 ; Illus. Zool. Invest., Crust, pi. Ivii. tigs. 2, 2 a. 



This species was described by McArdle from a single 

 specimen (female) dredged in the Arabian Sea at Sta. 279 



