107 

 61. Heterocarpus ensifer, A. M. Edw. 



Heterocarpus ensifer, A. Milne Edwards, Ann. Sci. Nat., Zool., (G) XI. 1881, Art. 4, p. 8, and Rec. de Fig. 

 Crnst., pi. 32: Spence Bate, Challenger Crust. Macrura, p. 638, pi. cxii. fig. 4: Borradaile, Stomapoda and 

 Decapoda of Willey's Exped., p. 413. 



? Pandalus carinalus, S. I. Smith, Bull. Mus. Comp. Zool., X. 1882, p. 63, pi. x. figs. 2-2/ and pi. xi. figs. 1-3. 



Heterocarpus carinatus, Wood-Mason, Ann. Mag. Nat. Hist., (6) IX. 1892, p. 369. 



Rostrum long, serrated dorsally and ventrally, continued nearly to the 

 posterior border of the carapace as a serrated carina. 



In addition to the postrostral crest, and in addition to the fine marginal 

 ridge, there are on either side of the carapace three well developed carinse. 



The 1st, or "post-ocular," is very indistinct as far as the cervical groove, 

 whence it is continued as a sharp carina to the posterior border of the carapace. 



The 2nd, or " post-antennular," runs without interruption from the posterior 

 border of the carapace into the orbital spine. 



The 3rd, or " post-antennal," runs from the posterior border of the carapace, 

 uninterruptedly into the branchiostegal spine. 



The 1st abdominal tergum has a faint median carina, and the 2nd a sharp 

 one which ends abruptly : the 3rd and 4th terga are also sharply carinated, but 

 the carina, in each, is produced posteriorly into a sharp spine. 



The legs and external maxillipeds though corresponding in structural 

 details with, and having inter se the same relations as, those of H. gibbosus, are 

 slenderer and very much shorter, none of them reaching beyond the antennal 

 scale. 



In the Investigator collection is a single young specimen, from the Andaman 

 Sea, 188-220 fathoms. As it is young and not in the best state of preservation, 

 I have merely recorded here the most obvious diagnostic points. 



Regd.No. 6 -^ 8 . 



62. Heterocarpus tricar inatus, Alcock & Anderson. 



Heterocarpus tncarinatus, Alcock and Anderson, Journal Asiatic Soc. Bengal, Vol. LXIII. pt. 2, 1894, p. 154. 

 Illustrations of the Zoology op the Investigator, Crustacea, Plate LI. Fig. 1. 



Rostrum, in the adult, about five-sixths the length of the carapace, strongly 

 recurved, continued as a high compressed serrated gastric carina that fades away 

 some little distance in front of the posterior border of the carapace : ventrally it 

 is armed with 7 to 10 teeth, dorsally with at least 7 not including 5 on the 

 gastric carina. 



The 1st, or " postocular," carina runs nearly to the posterior border of the 

 carapace ; the 2nd, or " postantennular " forms merely a buttress to the strong 

 orbital spine ; the 3rd, or " postantennal " fades away on the anterior part of 

 the branchial region. 



