COPEPODA 



773 



70 (67) First segment of right exopodite of male fifth foot has hyaline 

 appendage 71 



71 (72) Hyaline appendage of first segment of exopodite of male fifth foot 

 at inner distal angle, endopodite of right foot about equals 

 first segment of exopodite. 



Diaptomus signicauda Lilljeborg 1889. 



FIG. 1200.. Diaptomus signicauda. A, abdomen 

 of female. X 118. B, fifth feet of male. 

 X 174- (Original.) 



The first segment of the abdomen of 

 the female has a digitiform process on 

 the right posterior border. Found in 

 mountain regions of western United 

 States. It represents a group of species 

 that are found in the mountain regions 

 of the western part of the United States. 

 The peculiar appendage of the first seg- 

 ment of the female abdomen has given 

 the name to the species, and is charac- 

 teristic of the group. Collections in the 

 Rocky Mountains and farther west are 

 likely to contain this or allied species. 



Length of female, 0.93 mm. 



Length of male, 0.9 mm. 



72 (71) Hyaline appendage of first segment of exopodite of male fifth foot 

 on inner distal half, endopodite of right fifth foot much 

 shorter than first segment of exopodite. 



Diaptomus siciloides Lilljeborg 1889. 



Found in the Mississippi Valley and west to California. As Z)7 oregon- 

 ensis is typical of the Northern States, so D. siciloides may be considered 

 as typical of a region a little farther to the south. It has been found from 

 Long Island on the east to the Rocky Mountains on the west, and, while 

 not the exclusive form, is more apt to be seen than any other,. especially 

 along the Ohio River. 



Length of female, 1.06 to 1.225 m na. 



Length of male, i.oi to 1.1125 mm. 



FIG. 1210. Fifth feet 

 of male Diaptomus 

 siciloides. X 122. 

 (Original.) 



73 (3, 8) Endopodites of first swimming feet composed of three segments. 74 



