1258 THE VOYAGE OF H.M.S. CHALLENGER. 



especially elongate, the head is above armed with a strongly forward curved horn. The 

 first and second segments of the body are about equally long, the latter somewhat 

 thickened towards the hinder end, where the second gnathopods are fastened. The two 

 following segments are very short, of equal length, and together as long or slightly 

 longer than the second segment ; the fifth segment is longer than the preceding, but 

 shorter than the two preceding together, and much longer than the two last seg- 

 ments together. In the younger $ on the other hand the first and second segments 

 of the bod)^ are not so long, yet longer than the third segment. In the $ the 

 first segment is tolerably short, much shorter than the second segment, which is 

 thickest in the front part, where the first [second] gnathopods are fastened ; the third 

 and fourth segments together are much longer than the other segments and furnished 

 with a large brood-pouch. The three hinder segments are in the female sometimes 

 furnished with spines, which were not found in any adult specimen of the $ , but only 

 in a younger one. The upper antennas are in the male especially elongate, and when 

 bent back reach the fifth segment of the body. The first joint of the peduncle is more 

 than a third shorter, but much thicker than the second and about as long as the very 

 thin third joint. The flagellum is longer than the third joint of the peduncle and 

 consists of 16 joints in the $ and 10 in the $ . The lower antennas are in the $ 

 much shorter than the upper, and reach to somewhat beyond the middle of the second 

 joint of the peduncle of the upper antennae ; the third and fourth [? fourth and fifth] 

 joints are about equally long, and the flagellum, the second joint of which is scarcely 

 a fourth of the length of the first joint, is slightly longer than the last joint of the 

 peduncle. The antennae are furnished with long groups of seta? on the lower margin. 

 In the $ on the other hand the antennae, especially the upper, are much shorter than 

 in the $ and when bent back do not reach the fifth segment of the body ; the second 

 joint of the peduncle is not much longer than the first, and the third is much shorter. 

 In the younger $ also the third joint of the peduncle is shorter than the first. The 

 lower antennas are in the % as compared with the $ much longer and reach beyond 

 the third joint of the peduncle of the upper antennae. The first gnathopods are alike 

 in both sexes and completely agree with those of C. linearis. The second gnathopods 

 are in the male especially elongate. The first joint is nearly as long as the segment of 

 the body to which it is fastened, and is prolonged downwards on the front apex in a 

 strong spine. The hand is as large as the first joint, becomes broader outwards and is 

 nearly club-shaped and rounded at the outer extremity ; the upper half of the hinder 

 margin is armed with three teeth, the two uppermost small, while the third is broad, 

 triangular. The finger, which is attached at the end of the hinder margin, is very 

 strong and armed with a little tooth at the upper part of the hinder margin. In the 

 younger $ the first joint of the gnathopods is shorter than the second segment of the 

 body and shorter than the hand, which is not so narrow. In the ? these gnathopods 



