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



in the female), somewhat compressed horizontally, almost parallel or 

 even a little incurved, and perceptibly though very slightly deflexed 

 from the base ; (2) the carapace is much more convex and swollen, with 

 the lateral epibranckial and the median posterior spines much smaller ; 

 (3) the chelipeds have the palm less enlarged, and the fingers nearly 

 straight, instead of arched ; (4) the anterior angle of the supra-orbital 

 eave, instead of being sharply produced, is obtuse. 



The Museum possesses specimens from the Orissa Coast and Gulf of 

 Martaban, and also from the Straits of Malacca. 



Hyastenus planasius, Ad. & White. 



Pisa planasia, Adams and White, ' Samarang ' Crnst., p. 9, pi. ii. figs. 4 and 5. 



Hyastenus planasius, A. Milne-Edwards, Nouv. Archiv. du Mus., VIII. 1872, 

 p. 250. 



Hyastenus (Chorilia) planasius, Miers, Zoology H. M. S. ' Alert,' pp. 182 and 196 ; 

 and ' Challenger ' Brachyura, p. 57. 



Hyastenus planasius, Walker, Journ. Linn. Soc. Zool. Vol. XX. p. 109. 



Carapace elongate-ovate, its surface smooth and polished anteriorly, 

 finely granulose posteriorly, and with scattered tufts of hairs : a small 

 eminence in the middle of the gastric region, and a small lateral epi- 

 brancbial spinule, in front of which latter there may be a line of gra- 

 nules : lateral margin with three spinules anteriorly, two of which are 

 on the pterygostomian region. 



The rostrum is formed by two parallel spines, the tips of which are 

 somewhat incurved, and the length of which is about one-sixth that of 

 the carapace proper. The supra-ocular margin is, as usual, very pro- 

 minent, and has its anterior angle somewhat produced. The antero- 

 external angle of the basal antenna! joint forms a distinct tooth visible 

 from above. The legs are tomentose with additional long scattered 

 seta? : the second pair ( 1st ambulatory legs) are, as usual, markedly the 

 longest, being half again as long as the carapace and rostrum : the dac- 

 tyli are short, stout, recurved, and serrated posteriorly. The chelipeds 

 are described by Adams and White as follows : — " small, slender, equal 

 in size, covered with scattered long stout hairs ; the third joint sub- 

 cylindrical, curved inwards and enlarged anteriorly ; fourth joint short, 

 rounded, and curved, with two small tubercles on the outer and upper 

 surface ; fifth joint rather slender, sub-cylindrical, laterally compressed ; 

 claws slightly gaping in the middle, curved inwards, and finely denticu- 

 lated." As, however, the male specimen figured does not seem to be 

 adult, these characters are perhaps changeable with age. 



In the Museum collection are a young male and female from Gan jam 

 and Arrakan. 



