574 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxviii. 



the protrusion of the egg cases this segment is a broad flask shape, a 

 little wider than long, with well-rounded sides, and a squarely-truncated 

 posterior border. Its width under these conditions is fully three- 

 fourths that of the carapace and sometimes more. 



But after the protrusion of the egg cases it assumes an elongated 

 spindle shape, wider posteriorly, and with a somewhat emarginate pos- 

 terior border. In this condition it is about one-fifth longer than wide 

 and narrows toward either end, its extreme width being less than two- 

 thirds that of the carapace. 



It is always contracted into a short, narrow neck where it joins the 

 free segment, and is wrinkled across this neck as though segmented. 

 The abdomen is short, but little more than half (0.64) the length of the 

 genital segment in females with egg cases, and about one-third its 

 width. It is two-jointed, the joints approximately the same length, 

 but the anterior one a little wider. 



Anal lamina? small, well separated, and somewhat curved in toward 

 each other. Egg cases short, half the length of the body, but about as 

 wide as the abdomen, and each containing 50 eggs. 



Anterior antennas short and closely appressed to the carapace; pos- 

 terior antennae stout, with a swollen basal joint bearing an accessory 

 spine and a strong terminal hook. 



First maxillae medium size with a blunt point and an enlarged base; 

 second maxillae very long and slender with an acuminate point. First 

 maxillipeds with an exceptionally stout basal joint, which is fully three 

 times the diameter of the terminal joint, this latter being the usual 

 weak type, a little shorter than ordinary and tipped with two strongly 

 curved claws. Furca a rounded Y-shape, the base being the same 

 length as the branches, but much narrower, while the branches are 

 stout, blunt, and strongly curved. First swimming legs short and 

 stout, with the usual terminal claws, the small seta at the corner, and 

 the three large plumose setae on the posterior margin of the terminal 

 joint. But these plumose setae differ from those in most species in 

 that the basal third is swollen in diameter and bordered not by plumose 

 hairs like the tip, but with spine-like projections. The seta nearest 

 the distal end has them on the outer margin only; the middle seta has 

 about half as many on the inner as on the outer margin, while the 

 inner seta has them on both margins equally. 



The basal joint of the second legs is very much swollen, while the 

 two branches are short and stout. The spines on the endopod are 

 slender and acuminate. The rami of the third legs are large and stand 

 out prominent^ from the edge of the basal lamina. The spine at the 

 base of the exopod is also large, well curved, and blunt. The fourth 

 legs are short and weak, not reaching to the center of the genital seg- 

 ment, three-jointed, with five spines of about the same length situated 

 close together along the outer margin. The two terminal joints are 



