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424 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 
which is armed with a minute spine, projecting forward just inside of the 
peduncle of the antenna; between these spines the edge of the front is 
upturned in a sharp marginal carina, which terminates each side in the 
spines themselves. The dorsal surface of this part of the carapax is 
convex in both directions, the protogastric lobes are protuberant and 
well marked, and nearly the whole surface is roughened, and more or 
less tubercuiose, with transverse scabrous elevations, which give rise to 
numerous hairs. The branchial regions are slightly swollen, so that the 
breadth of the carapax posteriorly is greater than in front. All the por- 
tions back of the cervical suture are smooth and membranaceous. 
The eye-stalks are about half as long as the carapax in front of the 
cervical suture, flattened and expanded distally, where they are about 
three-fourths as broad as long. The eye itself is black, and the cornea 
extends round either side so as to be crescent-shaped as seen from above. 
The ophthalmic scales are less than half as long as the eye-stalks, nar- 
row, triangular, and acute. 
The first and second segments of the peduncle of the antennula are 
subequal in length, and the ultimate segment nearly once and a half as 
long as the penultimate, and almost as long as the eye-stalks. The 
superior, or major, flagellum is nearly as long as the ultimate segment 
of the peduncle; the thick, ciliated basal portion consists of about four- 
teen segments, and the slender terminal portion, which is nearly once 
and a half as long as the basal, of about five very slender and subequal 
segments. The minor flagellum is about two-thirds as long as the major, 
and composed of about eight segments. The peduncle of the antenna 
reaches by the eye nearly the length of the last segment, which is about 
as long as the greatest diameter of the eye. The acicle is slender, acute, 
and slightly longer than the last segment of the peduncle. The flagel- 
lum reaches beyond the tips of the ambulatory legs. 
The chelipeds are slender and very nearly equal in length, but the 
right is very much stouter than the left. In the right cheliped the 
merus and carpus are subequal in length, together nearly twice as long 
as the carapax, and both are rough and obscurely spinous, the spines 
being most conspicuous on the edges of the upper surface of the carpus, 
which is fully three times as long as broad, flattened above, and angular, 
but not distinetly carinated along either side. The chela is not far 
from twice as long as the carpus, nearly three times as long as broad, 
compressed vertically, evenly rounded, smooth and nearly naked above, 
but clothed with long, soft hair beneath; the digits are longitudinal, 
not gaping, and the dactylus is about two-thirds as long as the basal 
portien of the propodus, and its prehensile edge is armed with a broad 
tooth near the middle. In the left cheliped the merus and carpus are 
similar to those of the right, but much more slender and a little longer; 
the carpus is about six times as long as broad, and the edges of the 
upper surface are rather more sharply angular than in the right; the 
chela is shorter than the right, but very slender, smooth, and nearly 
