470 Wisconsin Academy of Sciences, Arts, and Letters. 



spines. The fifth segment of the female has a projecting tooth 

 at the middle of the dorsal surface. 



The first abdominal segment of the female exceeds the rest 

 of the abdomen in length. It is much dilated in front. The 

 lateral dilatations are rather slight, at the proximal fourth of 

 the length, and armed with minute spines. The second and 

 third segments are about equal in length, and each is somewhat 

 shorter than the f urea. The furcal rami are longer than broad 

 and ciliate on the inner margin. 



The antennae are 25-segTnented and reach to the end of the 

 furca. The right antenna of the male is much swollen anterior 

 to the geniculating joint ; the antepenultimate segment bears a 

 stout hook which is about one-half the length of the penultimate 

 segment. 



The spines on the posterior surface of the first basal seg- 

 ments of the female fifth feet are prominent. The lateral hairs 

 of the second basal segments are slender. The length of the 

 first segment of the exopodite is more than twice its width. 

 The second segment is prolonged into a hook of slight curva- 

 ture, and is denticulate on the inner margin. The third seg- 

 ment is distinct and armed with two spines. The endopodite 

 is one-segmented, about one-half the length of the first segment 

 of the exopodite, and setose at the tip. 



The first basal segments of the fifth feet of the male are 

 each armed with a prominent slender spine as in the case of 

 the female fifth feet. The second basal segment of the right 

 foot is as broad as long. It has a tooth-like process at the 

 middle of its inner margin and a small hyaline process on the 

 posterior surface near the distal end of the segment. The lat- 

 eral hair is near the distal end. The first segment of the ex- 

 opodite is short, its length being a little more than one-half its 

 breadth. It is produced at the outer distal angle, and bears a 

 small fold on the posterior surface near the distal end. The 

 second segment is stout, its length being to its breadth in the 

 proportion of three to two. The lateral spine is situated to- 

 wards the distal end, is straight, and equals in length the two 

 segments of the exopodite. The terminal hook is slender, and sa 



