764 



FRESH-WATER BIOLOGY 



38 (37) Antennal process of male exceeds ultimate segment, antennae 

 reach furca Diaptomus wardi Pearse 1905. 



Washington. 



Length of female, 2.9 mm. 



Length of male, 1.6 mm. 



Fig. 1 191. Diaptomus wardi, male. A, fifth feet. 

 X 173- B, terminal segments of right antenna. 

 X 112. (After Pearse.) 



39 (36) Small. Lateral spine of second segment of right exopodite of 

 male on proximal half of segment, antennae reach beyond 

 furca 40 



40 (41) Lateral spine of second segment of right exopodite of male fifth 

 foot short, right endopodite rudimentary, endopodites of 

 female fifth feet rudimentary. 



Diaptomus minutus Lilljeborg 1889. 



Northern United States and north 

 to Greenland and Iceland. It is one 

 of the most easily recognized species 

 because of the broad, saber-like hook 

 on the right fifth foot of the male and 

 the rudimentary endopodites of the 

 fifth feet of both sexes. It is common 

 in the waters of the Great Lakes, but 

 that is as far south as one may expect 

 to find it. 



Length of female, i to i.i mm. 



Length of male, i mm. 



Fig. 1192. Diaptomus minutus. v4, fifth foot 

 of male. X 154. B, fifth feet of female. 

 X 200. (Original.) 



