118 
The following points, therefore, are common to the four 
species : — The carapace is snb-pyriform, more or less acutely 
pointed medianly on the posterior border, convex, usually 
more depressed anteriorly than posteriorly : the rostral horns 
are well developed and divergent and usually curved out- 
wards ; the posterior part of the orbit is widely open, the 
upper margin consists of, first, an anterior portion forming 
an arch over the socket of the eye-peduncle, spined or pro- 
jecting each end ; second, an intermediate spine more or less 
distant from the posterior end ; and third, a strong, post-ocu- 
lar spine, usually pointing forwards, and distant from the 
intermediate spine at a lower level. 
The lateral spines of the carapace are, viz., one on the 
hepatic region, and three on the branchial, the most posterior 
of which approaches nearer the middle of the carapace. 
The basal antennal joint has a strong spine at the exter- 
nal distal angle, and usually a small one at the internal 
angle. There is a small conical tubercle close to the base of 
this joint, on the outer side, usually tipped with hairs. 
The external maxillipeds have the ischium joint with its 
internal distal angle very much produced above the trans- 
verse line. The merus joint, inverted-triangular in shape, is 
rounded and produced at its external distal angle partially 
covering the end of the exopod, truncate, and the margin 
insinuate at the internal angle ; the ends of the margin thus 
defined are acute or spined, the following joint originating 
close to the outer (or upper) end of this margin. 
Sub-hepatic and pterygostomial regions each with a more 
or less conical tubercle. 
Chelipeds usually rather weak in the females and in some 
males, in others much enlarged, with the fingers widely gap- 
ing, but not unsymmetrical. The merus has a spine at the dis- 
tal end above. The carpus is strongly keeled in the males. 
Ambulatory legs long, becoming successively shorter be- 
hind, the joints mainly cylindrical, the ischium joints each 
with a small conical tubercle below at the distal end, the 
penultimate joints more or less expanded towards their distal 
ends, the expansions usually becoming wider on the more pos- 
terior legs. The dactyli curved, sharp, with two rows, of 
small teeth. 
Pleon seven- jointed in the males, the fourth, fifth, and 
sixth coalesced in the females. 
The species of this genus are, as in other Maioid genera, 
well supplied with more or less curved corneous bristles 
springing in groups usually from the tubercles, rostral horns, 
etc., and also from the ambulatory legs. These are used for 
the attachment of foreign substances for purposes of obscura- 
tion. 
