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



Front small,, somewhat triangular, projecting little or not at all 

 beyond the level of the orbits, bilobed. 



Orbits small, circular : eyestalks short and thick. 



The antennules fold nearly vertically beneath the front. 



The basal joint of the antennas is very broad, and fills a "wide hiatus 

 at the inner angle of the orbit : the flagellum is short usually. 



There is no distinct epistome ; but the endostome is prolonged, 

 as far as the antennulary fossa3, in the form of a canal, which is divided 

 longitudinally by a deep vertical septum into two channels, each 

 channel being completed below by a lamellar process from the first pair 

 of maxillipeds. 



The external maxillipeds do not meet across the mouth, but leave 

 exposed between them the mandibles, and, in front of them, the afore- 

 mentioned plate-like prolongations from the first pair. of maxillipeds. 



The chelipeds are very large, and in flexion are closely apposed to 

 the front half of the carapace, so as to form a sort of buckler : the 

 meropodite, or " arm," has near its distal end, externally, a transverse 

 wing-like expansion, complementary to the wing-like expansions of 

 the carapace : the propodite, or " hand," is strongly compressed, its 

 upper border forming a high, sharply dentate or crenulate, crest. 

 Except for the fingers, the chelipeds are equal and symmetrical ; both 

 the fingers, namely, of one hand have on their outer aspect, near the 

 base, a stout projecting lobule. 



The abdomen in the adult male* consists of only five separate 

 pieces, owing to the fusion of the 3rd, 4th and 5th somites. In the 

 young male, as in the adult female, it consists of seven separate 

 somites. 



Key to the Indian species of Calappa. 



I. Extreme length of the carapace either quite 

 or nearly equal to its extreme breadth : — 



1. Carapace as long as broad : clypeiform 



expansions ill developed : — 

 i. Carapace sub-circular, with 7 longi- 

 tudinal parallel lines of bullous 

 tubercles ... ... G. pustulosa. 



ii. Carapace sub-quadrangular, without 



regular lines of tubercles ... G. wood-masoni. 



2. Carapace a little broader than long : clyp- 



eiform expansions well-developed ... G. gallus. 



* ? C. gallus, of which species I hare not seen adult males. 



