476 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxiii. 



coincides with that of the latter; anal laminae narrow and oblong, 

 nearly three times as long as wide, each armed with four small setae. 

 Dorsal surface of the abdomen and anal laminae visil)le tlu-ouah the 

 posterior sinus between the dorsal plates of the genital segment. 



Appendages the same as in the female, the only differences being 

 that the second antennae and second maxillipeds are larger, and there 

 are more spines on the swimming legs. The fourth legs are fully as 

 degenerate as in the female, being enlarged into broad lamina;, with 

 no signs of segmentation. The third legs are like the second pair 

 and are not enlarged; each ramus is two-jointed, the joints about 

 the same size, but those of the exopod nearly three times the size of 

 those in the endopod. 



The terminal joint of the endopod in these third legs is armed with 

 a single long spine or claw, curved strongly outward, which seems to 

 be characteristic of the genus. There are no plumose setae on the 

 swimming legs, the spines being arranged as follows: First exopod, 

 0, 1, endopod, 0, 0; second exopod, 1, 5, endopod, 0, 5; third exo- 

 pod, 1, 6, endopod, 0, 4; fourth exopod, 3, endopod, 1. 



The spermatophore receptacles are very large and elliptical in out- 

 line; they are situated in the posterior portion of the genital seg- 

 ment, and are inclined at an angle of about 45° to the central axis; 

 the ducts at their anterior ends are large and profusely coiled. 



Color as in the female, but the spermatophore receptacles are a 

 deep purple, and the ducts leading to them a lighter purple. 



Total length, 10 to 15 mm.; length of carapace on mid-line, 5 to 

 7 mm.; width of same, 6.5 to 8 mm.; length of fourth segment plates, 

 4.25 nun.; width of same, 6.75 mm.; length of genital segment, 

 6.75 mm.; width of same, 5.75 mm. 



Chalimus.— A male chalimus 8 mm. in length was among the speci- 

 mens examined, and the following description shows the points in 

 which it differs from the adult. 



Carapace the same shape as that of the adult, but much more 

 prominent anteriorly, relatively larger, and showing on its dorsal 

 surface areas similar to those in the Pandarinae; no eyes visible. 



The entire front of the carapace is occupied by the large attach- 

 ment gland, which is acorn-shaped, one- third the entire length of the 

 carapace, and as wide as long. It gives origin to two broad, flat, 

 ribbon-like frontal filaments, similar to those found on tbe Perissopus 

 chalimus, the stumps of which can be plainh^ seen at the center of the 

 frontal margin. 



Second and third thorax segments narrower and longer than in the 

 adult, with the lateral lobes hardly appearing on their sides. 



Fourth segment plates divided to their very base; genital segment 

 and its dorsal plates the same as in the adult, except that the posterior 

 sinus is much broader and shallower. 



