54 THE ROYAL SOCIETY OF CANADA 



inner ramus; the inner ramus is slightly longer than the outer but 

 rather blunt. The maxilliped is slender; the distal joint is provided 

 with a long seta that reaches almost to the tip of the joint. Furca 

 with stout, flaring rami, the flare being largely on the inside, the sinus 

 somewhat key-hole-shaped, the base broad. 



First swimming leg with the basal spine short and blunt and a 

 small spine at the distal end of the intermediate joint. Second swim- 

 ming leg slender, the joints of both exopod and endopod relatively 

 long; the spine on the basal joint long and slender and a small spine 

 at the distal end of the second joint. Third swimming leg of the usual 

 type. Fourth leg well developed, the basal joint slightly longer than 

 the next two, without spine or seta; the second joint provided with a 

 short claw; the third joint is longer than the second and is provided 

 with a spine distally; the terminal joint is shorter than the third; it 

 has three well-developed setae and a claw. Fifth and sixth legs are but 

 little developed, only a small portion of the setae showing in dorsal view. 



Total length 7-7 mm., length of carapace 4-45, width 4-3, length 

 of genital segment 2-2, width 2-8, egg strings 4 • 6. 



Male. Male about half the length of the female. Carapace 

 rounded, length and breadth equal; sinuses relatively deeper and 

 lateral lobes larger than in the female. Free segment wide and long, 

 not distinctly separated from the genital segment. Genital segment 

 slightly broader than long, well rounded anteriorly and posteriorly; 

 the fifth and sixth pairs of legs are not large; each is provided with 

 three setae. Abdominal segment broader than long of similar width 

 throughout. Anal laminae well separated and distinctly projecting, 

 each with four strong setae. 



In the appendages the main differences, as compared with the 

 female, are in the second antennae and first maxillae. The distal joint 

 of the second antenna has a laterally projecting hook on each side, 

 near the distal end, almost as prominent as the main portion of the 

 joint. Besides these there is a long seta attached near the middle of 

 the length, which extends almost as far as the claw. The first maxilla 

 has three rami instead of two, or it seems as though the inner ramus 

 was split in two throughout its length ; the outer ramus and the base 

 resemble those of the female. 



Length 3-8 mm., length of carapace 2-3, width 2-3, length of 

 genital segment 0-7, width 0-8. 



Colour: Uniformly white. 



Scores of specimens of this species were obtained and without 

 exception they were so much covered with parasites that it was a 

 difficult matter to be sure of the more minute surface structure. 



