92 BULLETIN OF THE 
The head is quadrate, widest across the posterior part of the eyes, which are 
oval, and more distinct than in the other species on our coast. A horizontal 
impressed line passes along the side of the head above and in front of the eye, 
and another just above the anterior margin oyer the bases of the antenne, 
The antennule (PI. I. Fig. 2 a) are short, not equalling the peduncle of the 
antenne. ‘Their basal segments are in contact above and in front; the second 
segment is short, the third as long as the first two, and is followed by a flagel- 
lum not as long as the peduncle and composed of about fourteen short and 
closely united segments. The antenne (PI. I. Fig. 2 b), when reflexed, reach 
the posterior margin of the third thoracic segment ; the first two peduncular 
segments are short; the third and fourth each twice as long as the second, and 
of somewhat greater diameter; the fifth is the longest peduncular segment, 
and, at base, only about half the diameter of the fourth. The slender, tapering 
flagellum is about twice as long as the peduncle, and composed of twenty-five 
or more segments. The fourth and fifth peduncular segments bear, near their 
distal ends, a few slender and rather short bristles, much less conspicuous than 
in C. concharum or C. polita (Pl. I. Fig. 1b), but longer than in the next species, 
C. impressa (Pl. I. Fig. 3b). 
The first thoracic segment is slightly longer than the second ; posteriorly 
the segments increase slightly in length to the fifth or sixth, but the seventh is 
the shortest. The first segment is marked by an impressed curved line just 
above the lateral margin. The epimera of the second and third segments are 
small, subquadrate, rounded behind. The fourth epimeron is larger than the 
preceding ones, with the lower posterior angle rounded. The fifth and sixth 
epimera are of about equal size and larger than the others, while the seventh 
is the smallest of all. In the last three the posterior margin is oblique, and 
the lower angle is pointed. All the epimera are quadrate in general outline, 
and from near the middle of the line of union with the segment a sharp 
depressed line extends upward upon each of the last four segments. 
In the first pair of legs (Pl. II. Fig. 1 a) the basis is flattened on the upper 
or inner side, and slightly curved in adaptation to the convex under surface of 
the head. The anterior margin of this segment is also fringed with bristly 
hairs. The succeeding segments are well armed with bristles, and the merus, 
carpus, and dactylus are armed along their palmar margins also with acute 
spines ; the carpus in this leg is triangular and articulated with little motion 
to the propodus. The legs of the second and third pairs resemble the first, but 
have a free articulation between the propodus and carpus, which is oval and 
armed with several acute spines. These three pairs of legs are directed forward. 
The fourth and subsequent pairs are directed backward. The legs of the fourth 
pair (Pl. II. Fig. 1b) are of moderate length and well armed with bristles or 
spines throughout, especially on the merus and carpus, where the spines form 
a striking feature. The palmar margin of both these segments is armed with 
a row of slender elongated spines and bristles, with many shorter spines also 
along the margin, while upon the outer or exposed surface of both segments is 
a pretty regular longitudinal row of short spines, nearly along the middle of 
