612 " THETIS " SCIENTIFIC RESULTS. 



Second antennae slightly longer and in both sexes considerably 

 stouter than first, but especially in the male ; fifth joint of 

 peduncle subequal in length to the fourth, each as long as, or 

 longer, than the flagellum, which has from five to seven joints, the 

 first always the largest, sometimes very much so in the male, 

 where the three or four terminal joints may be abruptly narrower 

 than the preceding. 



Upper lip bilobed. Third joint of mandibular palp as long as 

 second, distally setose. Inner plate of first maxillae oval with 

 setule on the almost pointed apex, and four spaced setae on the 

 inner margin at a little distance from the apex. Inner plate of 

 second maxillae rather the smaller, with lateral setae. Inner 

 plates of maxillipeds reaching beyond first joint of palp, outer 

 reaching nearly to end of the long second joint; fourth joint of 

 palp short, with small spine or unguis attached to its truncate 

 apex. 



First gnathopods much alike in the two sexes, the fifth joint 

 rather longer than the sixth, these two joints like the side-plates 

 being rather larger in the female than in the male. The palm of 

 the somewhat filiform sixth joint is longer than the hind margin, 

 and is matched in the male and overlapped in the female by the 

 curved finger. 



The second gnathopods are much more powerful in the male 

 and difierently shaped from those of the female. The fifth joint 

 in both is short, cup-shaped with a narrowed lobe between the 

 fourth and sixth joints. The latter in the male has a breadth 

 fully four-fifths of the length, with the hind margin produced into 

 a powerful tooth, against which the unguis of the strongly arched 

 finger impinges, enclosing a great cavity with another strong 

 tooth at its distal extremity near the hinge of the finger. The 

 much smaller sixth joint in the female has a breadth two-thirds 

 of the length and a sloping sinuous palm, over which the finger 

 closes, leaving only one or two shallow cavities. 



The peraeopods are in near agreement with those of C. mega- 

 cheles. In the first and second pairs the second and fourth joints 

 are somewhat expanded. In the three following pairs the second 

 joint is much expanded, the breadth being equal to the length in 

 the third pair, but exceeded by it in the other two. The third 

 pair is the shortest, the fifth the longest. In the male specimen 

 figured the terminal joints of all three pairs were reversed, but 

 apparently as a rule this is more the habit of the third than of 

 the other two pairs. 



In the first uropods the peduncle is considerably, in the second 

 a little, longer than the rami, which in each pair are subequal. 

 In the third uropods the peduncle is as broad as it is long. The 



