yee PROCEEDINGS OF THE NATIONAL MUSEUM. 239 
described hitherto. A conspicuous groove defining the inner angle of 
the branchial region ends anteriorly in a round pit and is interrupted 
posteriorly at the widest part of the cardiac region, behind which 
point it is continued almost to the posterior margin and unites with a 
broad irregular depression occupying the posterior portion of the 
branchial region; another short groove on the branchial region near 
the inner angle. There isa pit at the inner angle of the hepatic region, 
and another further back, between the gastric and branchial regions. 
The spines of the carapace are stout and blunt pointed. There are 
nine on the median line: four on the gastric, one on the genital, two 
on the cardiac, and two on the intestinal region. There is a spine on 
the frontal region on either side of the median line from which a ridge 
extends forward to the rostrum, which is either tuberculous or armed 
with a small spine. Between these ridges there is a broad, shallow 
depression. On each gastric region there is a spine which forms a 
T with those on the median line. There is a line of seven spines begin- 
ning at the summit of the hepatic region and terminating with the last 
antero-lateral spine. There two other strong antero-lateral spines, one 
at the prominent angle of the hepatie region, and one on the branchial, 
region midway between the other two. There are four additional 
spines on the branchial region: one between the first and second 
lateral spines, but a little higher up and smaller; one, small, near the 
anterior border; two larger, of which one is near the inner angle, 
and one at some distance posterior, and nearerthe margin; a fifth, near 
the cardiac region, is sometimes wanting, and in one specimen is accom- 
panied by another at a little distance. On the anterior margin of the 
hepatic region at the base of the lateral spine are one or two small 
irregular spines directed forward. In some specimens there is a small 
spine on the vostero-lateral margin just back of the last antero-lateral 
spine. 
tostrum depressed, flattened vertically, composed of two broad 
spines coalesced for from one-third to more than one-half their length, 
their outer margins slightly converging. 
Orbits with a single closed fissure above and below and prominent 
preocular and postocular spines. Orbital opening very small in pro- 
portion to the size of the carapace. Basal antennal joint broad, with a 
Spine at the base of the second joint, directed downward and forward, 
and a little smaller spine on the anterior margin near the outer angle. 
Merus of external maxilliped strongly notched at its antero-internal 
angle, slightly rounded at its antero-external angle. Tooth near the 
distal extremity of the inner margin of the exognath large, acute. 
There are several tubercles on the pterygostomian region, and some- 
times a small spine on the subbranchial above the base of the first am- 
bulatory leg. Abdomen with a longitudinal carina which is broader 
in the female than in the male; a spine or spiny tubercle on the first 
segment, and a tubercle on the second, 
