50 THE ROYAL SOCIETY OF CANADA 



nearly half the length of the carapace, considerably wider than long, 

 well rounded anteriorly and posteriorly. Abdomen small, one-third 

 the length of the genital segment, length and width nearly equal. 

 Anal laminae large, curved outward, each one supplied with three long 

 and one short setae and a short spine placed just dorsad to the inmost 

 seta. 



The two joints of the first antennae of nearly the same length, 

 well supplied with setae. The second antennae quite long, with the 

 terminal hook sharply curved; a short, stout spine is attached to the 

 basal joint. Maxillary hook stout, shorter than the claw of the second 

 antenna. Rami of first maxilla somewhat dissimilar; the outer one is 

 distinctly flanged, with a distinct constriction at the base, the inner 

 slightly longer, without a noticeable flange, with its axis in a slightly 

 different plane; neither branch is as long as the basal portion. The 

 second maxillae are long and slender, the second joint being half as 

 long again as the first. Maxillipeds stout, with the second joint 

 almost as long as the first, the accessory spine scarcely noticeable. 

 Furca short but very wide, wider at the tip than it is long and nearly 

 this width throughout; the sinus between the rami reached half way 

 to the base of the joint and the base of the sinus is made up of two 

 concave portions meeting in the middle line; each ramus is bifid, each 

 with a secondary sinus shaped like an inverted V; the four points thus 

 formed are rather abruptly pointed but not rounded; the secondary 

 sinuses are not so deeply cut as the primary sinus. 



The first swimming legs are of medium length, the second joint 

 being the longest; the first joint has a small spine on its antero-lateral 

 border and a stouter one on its postero-lateral ; the four setae on the 

 terminal joint decrease in length distally, the most distal being as 

 short as the shortest of the three terminal claws. There is a long seta 

 on the basal joint of the second leg; the second joint is longer than 

 broad; the exopod and endopod are much the same length; the inner 

 side of the second joint of the endopod projects beside the terminal 

 joint so that the setae on the end of it are in line with the setae on the 

 terminal joint. The spine at the base of the third leg is stout and 

 blunt. The fourth legs are four-jointed; the first joint is stout with 

 a spine at its distal end; the third joint has a short, stout spine dis- 

 tally and the terminal joint has three spines. The fifth legs are well 

 defined but do not show dorsally. 



Total length 4-7 mm., length of carapace 2-9, width 2-9, length 

 of genital segment 1-3, length of abdomen 0-3, length of egg strings 

 3-1. 



