404 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxni. 



plate. The latter is ovate, one-third longer than wide, and the 

 posterior lobes of the genital segment reach about to its center. Its 

 broad posterior end is evenly rounded with a smooth margin, while 

 the narrowed anterior end is slightly reentrant on either side. The 

 ventral plate of the abdomen is short and broad, its posterior margin 

 straight or a little concave, and reaching nearly to the tip of the 

 sixth segment plate (fig. 131). 



The anal laminae point diagonally outward and backward at an 

 angle of 45° with the central axis; their thickened outer margin is 

 nearly straight and slightly enlarged where it joins the abdomen. In 

 young females it is furnished with two wings, the ventral one tri- 

 angular in shape and extending from the base to about the center 

 of the lamina, the dorsal one of uniform width and extending the 

 whole length of the appendage. This dorsal wing is cut diagonally 

 at the distal end and furnished with one or two small teeth. In 

 mature females the wings are more or less absorbed and the thick- 

 ened margin becomes cylindrical, with two prominent teeth on its 

 inner side. 



The basal joint of the first antennae is large, heavily armed on its 

 ventral surface with setae, and nearly covered by the frontal plate. 

 The terminal joint is peculiar in that it is strongly flattened dorso- 

 ventrally, and each edge is rolled over ventrally toward the center; 

 this joint is also destitute of setae. The second antennae are com- 

 paratively very large; the basal joint is considerably larger than the 

 pad connected with it; the terminal claw is also stout and armed 

 with two accessory spines. The adhesion pads of the first pair are 

 obovate, nearly twice as long as wide, with the outer margins straight. 

 Those of the second pair are circular, their diameter the same as the 

 width of the first pair; they are separated by a greater distance than 

 is common in this genus. The third pair are club-shaped, three 

 times as long as wide, and narrowed anteriorly to a long blunt point. 

 The fourth pair are elliptical, twice as long as wide, and inclined at 

 an angle of 30° to the body axis. The mouth-tube and mandibles 

 show nothing peculiar; the second maxillae have a short and circular 

 exopod and a long, tapering endopod, which reaches beyond the 

 center of the tube; each ramus is tipped with a spine. 



First maxillipeds of the usual pattern; second pair enlarged, but 

 relativeh" smaller than in hicolor, the forceps knobs close together 

 and standing prominently above the surface. 



First swimming legs very small and rudimentary, the exopod boot 

 or foot shaped, the leg and heel being thick and swollen, while the 

 toe is long and slender. There is one spine at the heel, another on 

 the bottom of the foot in the instep, and two on the joint of the great 

 toe. The endopod is two-thirds as long as the exopod, with a well- 

 defined incision on the inner margin, representing the groove between 



