484 Wisconsin Academy of Sciences, Arts, and Letters. 



"The antennae are 25-segmented and reach the furca, or 

 sometimes the end of the furca. The right antemia of the 

 male is swollen anterior to the geniciilating joint; the antepe- 

 nultimate segment has a lateral lamina which is prolonged at 

 the end of the segment into a hook which barely reaches the 

 end of the penultimate segment. 



"In the female fifth foot^ the spines of the first basal seg- 

 ments are large. The second segment of the exopodite has a 

 strongly curved hook, which is denticulate on the inner mar- 

 gin. The third segment of the exopodite is distinct, and 

 bears two spines. The endopodite is one-segmented, hardly 

 equaling in length the first segment of the exopodite; the tip 

 is armed with two spines and is setose. 



"In the male fifth feet, the spines of the first basal segments 

 are large. The second basal segment of the right foot is 

 quadrate, rather longer than broad. The first segment of the 

 exopodite is quadrate and shorter than the second basal seg- 

 ment. The second segment of the exopodite is three times as 

 long as broad, convex on the outer margin and concave on the 

 inner. The lateral spine is at about two-thirds its length, 

 and is rather short. The terminal hook is symmetrically 

 curved and nearly equal to the combined length of the rest of 

 the exopodite and of the second basal segment. The right en- 

 dopodite is one-segmented, setose at tip, and equal in length to 

 the first segment of the exopodite. 



"The left fifth foot of the male reaches the end of the first 

 segment of the right exopodite. The first segment of the ex- 

 opodite is oval. The second segment is nearly equal in length 

 to the first ; it terminates in two strong spines, and has a setose 

 lamina at its base on the inner margin. The endopodite is one 

 segmented, setose at tip, and reaches to the middle of the 

 second segment of the exopodite. The animal is for the most 

 part colorless, but sometimes is blue or red. 



"Length of female, 1.1 to 1.2 mm." 



Locality, the tank of the city works at Albuquerque, New 

 Mexico. 



The above is the description of Herrick, and the figures of 



