262 A. Alcock — Carcinological Fauna of India. [No. 2, 



gonal, the anterior and posterior borders of both, joints sharply laci- 

 niate or serrate, as is also the outer edge of the carpus. 



Key to the Indian species of the sub -genius Platylanibrus. 



fl. Infra-orbital lobe entire and 

 strongly produced at the in- 

 ner (inferior) angle to form 

 a great spine plainly visible 

 chelipeds with their sur- i from above on either side of 



I. Carapace with three dis- 

 tinct carina?, one median, and 

 one, obliqne, on either side : 



Clieiipeus Willi Llieil oui- j uum auuvc un ciuici Blue ui 



faces (but not their edges) ] the rostrum .... .. L.^prensor. 



for the most part smooth : 



2. Infra-orbital lobe deeply 

 cleft, the inner portion not 

 ^ or hardly visible from above L. carinatus, Edw. 



ambulatory legs, with few 

 spines 



II. Carapace covered with great mushroom-like or paxilliform 

 tubercles : chelipeds with their surfaces very strongly 

 spinate or tuberculate : ambulatory legs strongly 

 spiniferous L, echinatus, 



Lambrus ( Platylambrus) prensor, Herbst. 



Lambrus prensor, Herbst, Krabben, II. ii. 170, tab. xli. fig. 3. 

 Lambrus prensor, Milne-Edwards, Hist. Nat. Crust., I. 358. 

 Lambrus jourdainii, F. de B. Capello, Jorn. Sci. Lisb., III. 1870-71, tab. 3, fig. 6. 

 Lambrus prensor, A. Milne-Edwards, Nouv. Archiv. du Mus., Vol. VIII. 1872, 

 p. 260 (foot-note) ; and Miss. Sci. Mex., Crust., I. p. 147 (foot-note). 



Lambrus prensor, Walker, J. L. S. Zool., Vol. XX. 1890, p. 109 (name only). 



Our numerous specimens correspond exactly with Capello's figure 

 and succint and graphic description. M. A. Milne-Edwards at first as- 

 signed Capello's species to L. carinatus, Edw., but afterwards to L. pren- 

 sor, and it is this last authority that I now follow. 



Carapace broader than long, broadly triangular with the sides round- 

 ed : the median and branchial regions are strongly prominent, the former 

 having three small spinules in the middle line, the latter having each 

 two oblique granular ridges, one of which is very faint and runs to the 

 large lateral epibranchial spine, the other of which forms a strong carina, 

 and runs to the large spine at the postero-lateral angle. The antero- 

 lateral margin is armed with 7 or 8 nearly equal-sized close-set compress- 

 ed teeth, behind which, at the lateral epibranchial angle, is a very large 

 blade-like spine : behind this again, on the postero-lateral border are two 

 large teeth, the outer of which, at the postero-lateral angle, is nearly as 

 large as the lateral epibranchial spine ; and lastly on the posterior bor- 

 der are three large curved spines. 



The rostrum is acute, concave at base, and slightly recurved at tip : 

 on either side of the rostrum is seen from above a very strong and 

 acute spine formed by the prolongation of the inner margin of the 

 infra-orbital lobe — this lobe is entire. 



