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 over the bases of the antennae. 

 The antennulse (PI. I. Fig. 2 a) are short, not equalling the peduncle of the 

 antennse. 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 antenna (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. 1 b), but longer than in the next species, 

 C. impressa (PI. 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 (PI. 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 (PI. II. Fig. 1 b) 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 



