20 PROCEEDIKGS OF THE NATIONAL MUSEUM vou 82 



The spines at the external distal angles of the furca are not so 

 broad as in E. lacustris, and the terminal setae are of equal width. 

 The interior margins of the furca are finely ciliate. 



The abdomen of the male (pi. 11, fig. 3) is strongly bent to the 

 right. From the second abdominal segment a process extends to the 

 right and is nearly as long as the width of the segment; it is re- 

 curved at the tip and both proximal and distal margins are sinuate 

 and the distal margin is armed with irregular teeth. The process of 

 the third segment extends to the right from the distal half of the 

 segment, is of about the same width through its length, and is 

 rounded at the end. There are two processes on the right of the fifth 

 segment, one a rounded hyaline plate, somewhat spatula-shaped, and 

 projecting forward from the dorsal surface to about the middle of 

 the third segment, and the other (pi. 11, fig. 7) a somewhat triangu- 

 lar projection from the ventral surface to the right; this latter 

 process bears five or six teeth, and extending down the dextral 

 margin of the process are minute serrations, which, near the junction 

 of the segment with the furca, are replaced by distinct teeth (pi. 11. 

 fig. 7). 



The first antennae of the female, according to Schacht, extend 

 slightly beyond the third abdominal segment; according to Lillje- 

 borg they do not reach the base of the furca. In the author's material 

 the length is somewhat variable and in many cases exceeds that of the 

 furca. 



In the fifth foot of the female (pi. 11, fig. 4) the second basipod 

 is longer than wide, the first and second segments of the exopod are 

 of about equal length and not much narrower than the second basi- 

 pod. The second basipod is armed on the outer border at about two- 

 thirds or three-fourths of its length with a small spine or seta. The 

 first segment of the exopod has, at its outer distal angle, a small 

 spine. The second segment has six spines, one on each side and four 

 terminal, the terminal being the larger. Forbes stated that a seventh 

 spine is sometimes present on the third segment. Though six is the 

 normal number, there is doubtless some variation in both number and 

 position. Seven have been found in specimens from Alaska ; in one 

 preparation (pi. 11, fig. 5) eight were found, and in this the positions 

 of the spines were different in the two feet. 



The right fifth foot of the male (pi. 11, fig. 6) is 2-segmented. 

 The first segment, which is really the second basipod, is more tjian 

 twice as long as broad, wider at the distal end, and bears upon the 

 inner distal margin a denticulate hyaline lamella. It has a delicate 

 seta on the external margin at about two-thirds its length. The 

 left foot does not differ from that in E. lacustrls. 



