190 A. Alcock —Carcinological Fauna of India. [No. 2, 
retractile towards the post-ocular tooth, which, however, affords no 
concealment. 
Chelipeds (in the female) hardly stouter than the ambulatory legs, 
which are short, with prehensile dactyli. 
Two ovigerous females, the larger of which is 4 millim. long, from 
off the Malabar Coast, 26 to 31 fathoms. 
The genus Collodes has hitherto been known only as a tropical 
American genus. It has been found on both sides of Central America 
so that its occurrence in Indian waters is not without precedent. 
Sub-family II. ACANTHONYCHIN^E. 
Eyes without true orbits : eye-stalks little movable, either short 
and more or less concealed beneath a forwardly-directed supra-ocular 
spine, or obsolescent and almost or completely sunk either in the sides 
of a huge beak-like rostrum, or between low pre-ocular and post-ocular 
excrescences (Sphenocarcinus) : a distinct post-ocular spine, which is 
not cupped, may be present ( Fugettia ). Basal antennal joint truncate- 
triangular. 
External maxillipeds with the merus as broad as the ischium, and 
with the (small) palp arising from the antero-internal angle of the 
merus. 
Dactyli of the ambulatory legs prehensile or sub-chelate, in the 
former case the last three pairs of legs are often disproportionately 
short compared with the second pair. Rostrum either simple or two- 
spined. 
Key to the Indian genera. 
I. Kostrum of huge 
size ; simple, or 
"bifid at tip; not 
flanked on either 
side by salient su¬ 
pra-ocular spines. 
1. Eye-stalks al¬ 
most obsolete, 
completely sunk, 
and almost or 
quite immovable:^ 
carapace smooth 
or tuberculate: no 
post-ocular pro¬ 
cess. 
i. Carapace and 
rostrum sub-cylin¬ 
drical, the latter 
bifid at tip. 
ii. Carapace de¬ 
pressed, elongate- 
triangular : ros- 
t r u m laterally 
compressed, not 
bifid at tip. 
Xenocarcinus. 
SlMOCARCINUS. 
2. Eye-stalks short, sunken but movable 
between low smooth pre-ocular and 
post-ocular excrescences : carapace with 
C huge symmetrical pedicled tablets. Sphenocarcinus. 
