444 A. Alcock — Car etiological Fauna of India. [No. 3, 



Of the legs the 2nd pair are the longest, being twice the length of 

 the carapace, and the 3rd pair are slightly shorter : the 1st pair are 

 nearly 1J times, the 4th pair about 1J times the length of the carapace. 



In the Indian Museum are 4 specimens, from the Andamans and 

 Nicobars: the carapace of the largest male is 14 millim. long and 16 

 millim. broad. 



Cardiosoma, Latreille. 



Cardisoma, Latreille, Encycl. Method. X. p. 685 (1825) : De Haan, Faun. Japon. 

 Crust, p. 27: Milne Edwards, Hist. Nat. Crust. IT. 22, and Ann. Sci. Nat. Zool. (3) 

 XX. 1853, p. 203 : Smith, Trans. Connect. Acad. Sci. II. 1870, p. 142 : Miers, 

 Challenger Brachyura, p. 219 : Ortmann, Zool. Jahrb., Syst., VII. 1893-94, p. 732. 



? Discoplax, A. Milne Edwards, Ann. Soc. Entom. France, (4) VII. 1867, p, 248, 

 and Nouv. Archiv. du Mas. IX. 1873, p. 293. 



Carapace deep, convex fore and aft, transversely oval, with the 

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

 expansion of the gill-chambers, the pterygostomian regions densely 

 tomentose. 



The fronto -orbital border is much more than half, and the deflexed 

 and nearly straight front is about a fourth, the greatest breadth of 

 the carapace. Orbits deep, with the outer angle denned by a denticle, 

 and with the tooth at the inner angle well developed but distant from 

 the front : the eyes are very loose in the orbits. 



The antennules fold obliquely beneath the front, by which they are 

 a good deal concealed : the inter-antennular septum is very broad. The 

 antennae lie in the orbital hiatus, which their broad basal joint nearly 

 fills : their flagellum is very short. 



Epistome short, prominent and well defined : buccal cavern elon- 

 gate squarish, the external maxillipeds do not close it bat leave between 

 them a rhomboidal gap in which the mandibles are exposed. In the 

 external maxillipeds the merus is a longish joint and carries the 

 palp, which is large and not at all concealed, at its antero-external 

 angle : the exognath, which carries a flagellum, is exposed in much the 

 greater part of its extent. The exognuths of the other maxillipeds are 

 heavily fringed with coarse hair. 



The chelipeds, which are much more massive than the legs, may 

 either be equal or markedly unequal, differing little in the sexes : they 

 alter considerably with age — one or both — the arm and fingers becoming 

 elongated, and the whole hand increasing in size until it becomes longer 

 than the carapace is broad and more than half as high as the carapace 

 is long. 



The legs are stout: some of their joints are fringed with bristles, and 



