COPEPODA 



763 



34 (33) Right endopodite of male fifth foot exceeds length of first segment 

 of exopodite, spines of first basal segments small. 



Diaptomus sicilis Forbes 1882. 



Found in the Great Lakes, being 

 the most abundant form taken in 

 limnetic collections; found to some 

 extent in other lakes in the same 

 general region. It is, as a rule, 

 confined to the larger and deeper 

 lakes. It is frequently found asso- 

 ciated with D. minutus but is read- 

 ily distinguished by the slender, 

 symmetrical, sickle-shaped hook 

 terminating the exopodite of the 

 right iifth foot of the male; this is 

 not a characteristic, however, that 

 will distinguish it from species 

 found in other localities. 



Length of female, 1.25 mm. 



Length of male, i.is mm. 



Fig. 1189. Diaptomus sicilis, male. A, terminal segments of 

 right antenna. X 194. B, fifth feet. X 194. (Original.) 



35 (27, 32) Process exceeds in length penultimate segment 36 



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



foot of male terminal or nearly so 37 



37 (38) Process of antepenultimate segment of right antenna of male only 



slightly longer than penultimate segment, antennae equal in 

 length to cephalothorax. 



Diaptomus shoshone Forbes 1893. 



Rocky Mountains. Not so widespread 

 or characteristic of the mountain lakes as 

 D. Tyrelli Poppe, although this giant spe- 

 cies is by no means uncommon, and is espe- 

 cially striking because commonly colored a 

 bright red. 



Length of female, 2.9 mm. 



Length of male, 2.5 mm. 



Fig. iigo. Diaptomus shoshone, male. A, fifth feet, 

 X loS. B, terminal segments of right antenna. 

 X 180. (Original.) 



