3$0 A. Alcock — Carcinological Fauna of India, [No. 3. 



■ >■'■ B. Exognath of the external maxillipeds 



as broad as or broader than the ischi- 

 ognath : dactyli of the legs com- 

 pressed but not broadened : — 



a. Carapace flat and depressed .... Ptychognathus. 



b. Carapace deepish, strongly con- 

 vex in both, directions Pyxidognathus. 



2. An oblique hairy ridge on the exposed surface of 

 the external maxillipeds (Sesarminze) : — 



i. Carapace little, sometimes not at all, broader 

 than long, the pterygostomian regions and 

 sidewalls with a sieve-like reticulation : lower 

 border of orbit not abnormally prominent : — 



A. Antenna? lodged in the orbital hiatus : — 



a. Carapace nearly square : front 

 abruptly and vertically de- 

 flexed Sesarma. 



h. Antero-lateral borders of cara- 

 pace arched : front obliquely 

 deflexed Sarmatittm. 



B. The tooth at the inner angle of the 

 lower border of the orbit meets the 

 front, so as to exclude the antennas 

 from the orbit : — 



a. Carapace dorsally smooth and 



nude Metasesarma. 



h. Carapace dorsally verrucose and 



densely tomentose Clistocceloma. 



ii. Carapace much broader than long, the 

 pterygostomian regions, etc., not reticulated : 

 lower border of orbit prominent beyond the 

 front. Front gradually declivous. General 



appearance much like Macrophthalmus Metaplax. 



II. The antennules fold nearly longitudinally in deep notches 

 in the front visible in a dorsal view {Plagusiinae) : — 



1. Merus of the external maxillipeds of good size and 



as broad as the ischinm Plagusia. 



• 2, Merus of the external maxillipeds small and mnch 



narrower than the ischium . Liolophcs. 



Sub-family Grapsin^e, Dana (pt.). 

 Grapsos, Lamk., Kingsley. 



Orapsus (part) Lamark, Syst, Anim. Sans Vertebr. : Latreille, Hist. Nat. Crust, 

 et Ins. VI. p. 56, and Gen. Crust, p. 32. 



Grapsus, Leach, Trans. Linn. Soc. XI. 1815, pp. 309, 323. 



Grapsus (part) Desmarest, Consid. Gen. Crust., p. 129, and Diet. Sci. Nat. 

 XXVIII. p. 247 : Milne Edwards, Hist. Nat. Crust. II. 83, and Ann. Sci. Nat., Zool., 

 (3) XX. 1853, p. 166 : Dana, U. S. Expl. Exp. Crust, pt. I. p. 336. 



