1895.] A. Alcock — Carcinological Fauna of India. 259 



3. Carapace transversely oval ; expanded laterally, 

 but not posteriorly : no ridge on the ptery- 

 gostomian region CEthra. 



Lambrus, Leach. 



Lambrus, Leach, Trans. Linn. Soc, Vol. XL 1815, pp. 308, 310. 

 Lambrus, Milne-Edwards, Hist. Nat. Crust., I. 352. 

 Lambrus, A. Milne-Edwards, Miss. Sci. Mex., Crust., I. p. 146. 

 Lambrus, Miers, J. L. S., Zool., Vol. XIV. 1879, p. 668 ; and ' Challenger ' Brachy- 

 ura, p. 91. 



Carapace either broadly triangular with rounded sides and pointed 

 front, or ovate-pentagonal with front pointed but extremely short : the 

 surface is granular, or tubercular, or spiny. 



The eyes are enclosed in distinct orbits, which have a suture above 

 and a hiatus below, the hiatus being occupied by the second joint (true 

 third joint) of the antennal peduncle. 



The antennules fold obliquely. The antennas are small : their basal 

 joint, which is extremely short, and does not reach the front, is wedged 

 in between the antennulary fossa and the large lobe that constitutes the 

 floor of the orbit. 



The buccal frame is usually quadrangular, but is sometimes a little 

 narrowed in front ; it is completely closed by the external maxillipeds : 

 the epistome is sometimes very large, sometimes narrow. 



The chelipeds are usually of immense size and length, out of all 

 pi'oportion to the short slender ambulatory legs : the meropodite and 

 "hand" are usually prismatic, with the borders strongly dentate: the 

 fingers are much shorter than the palm, and are abruptly curved in- 

 wards and a little downwards. 



The abdomen of the female usually consists of seven segments ; that 

 of the male of five or six. 



Professor A. Milne-Edwards, (Miss. Sci. Mex., Crust., I. pp. 146- 

 148) subdivides the genus Lambrus into ten sub-genera, the indepen- 

 dence of all of which, however, is not universally admitted. 



The sub-genera at present known to exist in Indian waters are 

 shown in the following 



Key to the Indian sub-genera of the genus Lambrus. 



I. Carapace tuberculate, ovate-pentagonal, the rostrum not 

 breaking beyond the general outline of the body : the 



buccal frame a little narrowed in front Lambrus. 



J. ii. 33 



