342 Carcinological Fauna of India. 



The Xanthasia sp., or Xanthasia Whitei, from Mei'gui, referred to 

 by de Man in Journ. Linn. Soc, Zool, XXIT. 1887-88, p. 106, pi. vii. 

 fiff. 1 is represented in the collection by a single small male and is 

 characterized by having the upi'aised edge of tlie carapace blunt and 

 i-ounded instead of thin and acute, and the medinn tubercle of the 

 carapace ill defined instead of sharply circumscribed : the posterior 

 marcrin of the carapace, also, is more prominent and is not quite contin- 

 uous with the lateral margins. The legs also are somewhat longer. 



Family OCYPODID^, Ortraann, emend. 

 Key to the Indian genera of Ocypodidoa, 



I. A hairy-edged pouch leading into the branchial cavity, 

 between the bases of the 2ad and 3rd pair of true 

 legs [_Ocypodinie'\ : — 



1. Antennular flagella rudimentary, completely 

 hidden beneath the front: antennas small, 

 almost rudimentary : eyes very large, occupy- 

 ing the greater part of the ventral surface of 

 the eyestalks : chelipeds very unequal in both 



sexes OcYPOPA. 3 ^J 



2. Antennular flagella small, not hidden beneath 

 the front: anteiinag of good size: eyes small, 

 terminal on the long slender eyestalks : in the 

 male only, one cheliped is enormously enlarged 



the other being very small Gelasimds. ^ j 6 



II. No pouch or opening between the bases of any of the 

 legs :— 



1, The antennules fold obliquely or nearly 

 vertically : curious membranous spaces, or 

 "tympana," are present on the meropodites 

 of the legs (Scopimerinx): — 



i. Tympana very well defined : external 

 maxillipeds very large and with a strong 

 almost hemispherical bulge forwards : — 



a, Merus of external maxillipeds larger 

 than the ischium : the distal end of 

 the 4th abdominal segment of the 

 male is fringed with bristles and 



overlaps the 5th segment DoTlLLA. ! ■< (,^: 



b. Ischium of external maxillipeds J 

 larger than the merus : the 4tli 

 abdominal segment of the male is 



normal, but the 5th is constricted 

 in part or all of its extent and gives 

 the abdomen a wasp-like appear- 



ance SCOPIMERA. 



684 



3,-bG^ 



