448 A. Alcock — Carcinulogical Fauna of India. [No. 3, 



In the Indian Museum are 18 specimens from the Nicobars and 

 Andamans (besides 4 from the " South Seas" and Madagascar). 



In life the carapace is dark violet and the chelae bright cinnabar red. 



Pelocarcinus, Edw. 



Gecarcoidea, Milne Edwards, Hist. Nat. Crust. II. 25 (1837). 



Pelocarcinus, Milne Edwards, Ann. Sci. Nat. Zool. (3) XX. 1853, p. 203, and 

 Archiv. du Mus. VII. 1854-55, p. L83 : A. Milne Edwards, Nouv. Archiv. du Mus. 

 (3) II. 1890, p. 171 (et synon.). 



Hylseocarcinus, Wood-Mason, J.A.S.B. XLII. 1873, pt. 2, p. 258, and Ann. Mag. 

 Nat. Hist. (4) XIV. 1874, p. 189. 



Limnocarcinus, de Man, Notes Leyden Mus. I. 1879, p. 65. 



Gecarcoidea, Ortmann, Zool. Jahrb., Syst., VII. 1893-94, pp. 732, 738. 



Carapace transversely oval, somewhat depressed, with the lateral 

 borders tumid and strongly arched owing to the vault-like expansion 

 of the gill-chambers : the gastric region particularly well defined. 



The extent of the fronto-orbital border is less than half the great- 

 est breadth of the carapace, that of the strongly deflexed and nearly 

 straight front is from a sixth to a seventh the greatest breadth of the 

 carapace. 



Orbits deep, broadly oval, demarcated dorsally by a sharpish slightly 

 raised border, their outer angle not defined, a wide gap in their lower 

 border : at the inner angle there is a strong tooth which may or may 

 not, even in the same species from the same jungle, meet the front r 

 if it does so, the antennae, which are much reduced in size, are excluded 

 from the orbit. 



The antennules fold obliquely beneath the front, and the inter- 

 antennular septum is not very broad. 



Epistome sunken, hairy posteriorly so as to appear ill defined from 

 the palate. Buccal cavern rounded anteriorly, not nearly closed by the 

 external maxillipeds, which leave between them a wide rhomboidal gap 

 in which the mandibles are exposed 



The external maxillipeds are rather short : their merus lies oblique- 

 ly, and its anterior edge is excavated for the insertion of the palp, 

 which is short and coarse and is completely exposed : their exognath 

 is very short and almost entirely concealed and is without a flagellum. 

 The exognaths of the other maxillipeds are heavily fringed with hair. 



Chelipeds much more massive than the legs, usually equal in both 

 sexes, though larger and longer in the male than in the female. 



Legs stout : in all, the anterior border of the carpus and all the 

 borders of the propodite and dactylus are spiny, there being six rows 

 of spines on the dactylus. 



