222 A. Alcock — Carcinohgical Fauna of India. [No. 2, 



51. Leucosia haswelli, Miers. 

 Leucosia haswelli, Miers, ' Challenger' Brachyura, p. 324, pi. xxvii. fig. 2. 



Carapace with the antero-lateral margins slightly sinuous, owing 

 to the slight convexity of the hepatic regions, which also are defined 

 posteriorly, on the dorsum of the carapace, only hy a faint crease. In 

 other respects the carapace almost exactly resembles that of L. longi- 

 frons, but is a little more convex. 



The front ends abruptly in a projecting, sharply transverse, sinuous 

 edge, the edge under a lens being seen to be faintly bilobed with each 

 lobule again faintly emarginate. 



The thoracic sinus is a roughly Y-shaped cavity of no great depth, 

 the tail of the Y being defined by four large pearl -like granules situated 

 above the base of the chelipeds, the concavity of the fork of the Y being 

 defined by the convex perfectly smooth edge of the pterygostomian 

 region, and the limbs of the Y being both equally short. 



The ventral surface of the ischium of the external masillipeds of 

 the female is moderately convex without a terminal tooth. 



The chelipeds are almostly exactly like those of L. longifrons ; but 

 on the upper surface of the arm there are always at least six pearly 

 tubercles, in two short lines, running forwards from the basal eminence 

 formed of coalescent granules, aad these tubercles, like some of those 

 on the inner edge of the arm, are of an uniform transparent blood-red 

 colour ; the wrist has a row of tiny blood-red granules along its inner 

 edge ; and the hand has not only a row of granules along its inner 

 edge, but also, below this, a row of punctuations which become granules 

 on the immobile finger : finally, the fingers are crenulate along the 

 whole extent of their opposed edges. 



Except that their propodites are sharply carinate, the legs exactly 

 resemble those of L. longifrons. 



Colours in spirit : light greenish yellow, mottled with darker, and 

 with a dark greenish brown blotch on the posterior part of either 

 branchial region and two white spots on either side of the gastric region. 



Size of carapace of an adult male 21 millim. long and 18 millim. 

 broad, of an adult female 22'5 by 20 millim. 



37 specimens, young and adult, of both sexes, from the Andamans, 

 are in the Indian Museum collection. In the smallest young the carapace 

 is more elongate and its posterior border is almost straight, its whole 

 shape being very much like that of L. marmorea, Bell. 



52. Leucosia pallida, Bell. 



Leucosia pallida, Bell, Trans. Linn. Soc. Vol. XXI. 18S5, p. 285. pi. xxx. fig. 2, 

 and Cat. Lencos. Brit. Mus. p. 7 : E. Nauck, Zeits. Wiss. Zool. XXXIV. 1880, 

 p. 48. (gastric teeth). 



