286 A. Alcock— Carcinological Fauna of India. [No. 2, 
convexities being granular : the rest of the carapace is somewhat con¬ 
cave. 
The chelipeds and ambulatory legs are rough : the chelipeds have 
the lower edge sharply dentate, and the outer edge of the carpus sharp¬ 
ly dentate : the ambulatory legs have the 3rd, 4th and 5th joints cari¬ 
nate or cristate above, and the 3rd and 5th joints cristate below : the 
dactyli are cristate on both edges, and end in little claws. 
The abdomen is deeply sculptured. 
In the Museum collection is a male from the Andamans, and a 
female from Ceylon. 
Sub-family II. EUMEDONINiE, Miers. 
Miers, Journ. Linn. Soc., Zool., Yol. XIV. 1879, p. 670. 
Carapace rhomboidal or pentagonal, with a spine at the junction of 
the antero-lateral and postero-lateral borders. Rostrum usually bifid 
or emarginate. Surface of carapace nearly flat. Chelipeds of moder¬ 
ate size and length. 
Key to the Indian genera of the sub-family EuMEDONiNiE. 
I. Floor of the orbit not in contact with the front, but leaving 
a hiatus which is more or less filled by the second joint 
of the antennal peduncle. Chelipeds armed with large 
spines : ambulatory legs compressed :— 
1. Spine of antero-lateral angle of carapaoe direot- 
ed forwards. 
2. Spine of antero-lateral angle directed straight 
outwards; last pair of legs dorsal in position... 
II. Floor of the orbit meeting the front, so as to completely 
exclude the antennal peduncle from the orbit: chelipeds 
not armed : ambulatory legs not compressed. 
Zebrida, Adams and White. 
Zebrida , Adams and White, ‘ Samarang ’ Crustacea, p. 23. 
Zebrida , Miers, J. L. S., Zool., Yol. XIY. 1879, p. 670. 
Carapace sub-rhomboidal, flattened, with the rostrum formed by 
two large, acute, laminar, almost parallel teeth ; and with the antero¬ 
lateral angles produced to form two similar laminar teeth projecting 
forwards in a plane parallel to the rostrum. 
Orbits circular, their inner canthus being filled by part of the 
antennal peduncle. 
The antennules fold obliquely. The antennae are entirely concealed 
beneath the rostrum : their flagellum is well developed; and their 
basal joint is longish, reaching to the inner canthus of the orbit. 
Zebrida. 
Eumedonus. 
Ceratocarcinus. 
