1900.] A. Alcock — Carcinological Fauna of India. 351 



angles, and are more or less sinuous and oblique: the eyestalks are 

 very long and are formed as in ' Ocypo da, but are much slenderer: tho 

 eyes, though chiefly ventral in aspect, are always terminal. 



The small antennular flagelln, which are not hidden under the 

 front, fold obliquely. The antennas, which stand free at the inner 

 nngle of the orbits, have well developed flagella. 



Epistome, though short, quite distinct. The lateral borders of the 

 buccal cavern are convex outwards, sometimes so much so as to give 

 the cavern a subcircular outline. The external maxillipeds have a long 

 ischium and a short and somewhat oblique merus with the coarse 

 flagellum jointed to its antero-external angle: they close the buccal 

 cavern except for a chink anteriorly. 



The chelipeds differ greatly in the sexes. In the female they are 

 equal, are shorter and slenderer than the legs, and have broad-tipped 

 spoon-shaped fingers. In the male one of the chelipeds resembles 

 those of the female, but the other is of relatively gigantic proportions, 

 the hand alone being often as big and heavy as all the rest of the 

 animal. 



The legs are stout and end in very sharp dactyli, and the meropo- 

 diies of at least the 2nd and 3rd pairs are foliaceous : these two pairs 

 are a little longer than the other two, being about twice the length of 

 the carapace. 



As in Ocypoda, the branchial cavity is capacious, and its lining 

 membrane thickened and vascular, with a fleshy lobe, shaped like a gill- 

 plume, projecting into the space between the tips of the last two gill- 

 plumes : also, between the basal joints of the 2nd and 3rd pairs of legs, 

 there is an orifice, thickly protected by hairs, leading towards the 

 branchial cavity. 



The abdomen of the male is narrow : in both sexes of all the Indian 

 species it consists of seven separate segments. 



Distribution : all the warmer regions of the globe, from the Atlantic 

 coasts of America eastwards (including the Mediterranean basin) to the 

 Pacific coasts of America again. 



The species of Gelasimus are, like the Ocypodes, gregarious, and live in warrens 

 in the mud-flats of tropical and subtropical estuaries. Their intelligence, like that 

 of the Ocypodes, is of a high order. 



In one species, at any rate (Gelasimus annulipes), the males, which are greatly 

 in excess of the females, use the big and beautifully-coloured cheliped, not only for 

 fighting with each other, but also for "calling" the females. I have described my 

 own observations on these points in the Administration Report of the Marine Survey of 

 India for 1891-92 — reprinted, as an extract, in the Annals and Magazins of Natural 

 History for 1892. 



The fact that the males greatly outnumber, and therefore are more 

 J. n. 46 



