58 STALK-EYED CRUSTACEA. 
between the eye-stalks, forming a blunt rudimentary rostrum. The gastric 
region is sharply defined, and presents an indistinct longitudinal furrow on 
each side of the median line it is lightly convex in both directions. The 
branchial regions of the right and left sides are strongly inflated, and sharply 
separated from one another by a re-entrant angle formed by the curving: 
forward of the posterior border of the carapace on each side of the median 
line. 
The eye-stalks are rather long and slender, being about equal in length 
to the anterior section of the carapace. The ophthalmic scales are very small 
and minutely bifid at the tip. The third segment of the antennular pedun- 
cle is about two thirds the length of the eye-stalk, and imcreases in diameter 
from the base to the distal end; the superior flagellum is rather longer than 
the distal segment of the peduncle, and its enlarged, ciliated basal portion 
forms rather more than one third of its whole length. The inferior flagel- 
lum is about one half as long as the superior, and is composed of about 
eleven segments. The peduncle of the antenna surpasses the eye-stalk by 
one half the length of its distal segment; the acicle is long and slender, 
tipped with a few sete; it reaches forward a little beyond the eye; the 
flagellum reaches beyond the tips of the ambulatory legs. The chelipeds are 
nearly alike in shape and size; their segments are clothed with long sete, 
which assume a tomentose appearance on the chelx; the carpus is about 
equal in length to the chela, its inner face is perpendicular, the inner mar- 
gin of the upper side is armed with seven small spines, and there is also 
a spine at the distal end of the superior margin; the chela is short and 
thick, the fingers about the same length as the basal portion of the propodite, 
slightly downeurved, meeting throughout their length, working horizon- 
tally. The ambulatory legs are of nearly equal length, surpassing the chelli- 
peds, setose, the carpus armed with a sharp tooth at the distal end of its 
upper side; the propodite is twice as long as the carpus, the dactylus is | 
considerably longer than the propodite, and like that segment is distinctly 
curved ; it is tipped by a small horny nail. The fourth pair of legs are but 
slightly subcheliform ; the rasp is formed of a single row of scales. j 
There are three small, rudimentary appendages on the left side of the : 
abdomen; the first and second of these are two-branched, the secondary 
branch being exceedingly minute. The sexual tube which issues from the 
coxal segment of the last thoracic appendage of the right side is very 
long. : 
