Ma/rsh — North American Species of DiaptomiLS. 407 



tinctly two-segmented, the left one-seg- 

 mented, washingtonensis — P'^v/- » 



The right endtxpoJite equals or only slightly ex- 

 ceeds the first segment of the exopodite. 

 The terminal segment of the right exoptodite 

 has a transverse ridge on its dorsal sur- 

 face, the lateral spine exceeds in length 



the segment, albuquerquensis ~ D^ ^ ' ' * 



The terminal segment of the right exopodite 

 does not have an oblique ridge on its dorsal 

 surface, the lateral spine is short, about OTie- 

 half the length of the segment novamexicanus ^ p'l'^'^' 



The terminal processes of the left exopodite are 

 digitiform, the right endopodite shorter than 

 the first segment of the exopodite, 

 The right endopodite triangular in form, first 



segment of the exopodite without hyaline -^, . 



appendage nudiis — p ' ^'^ ^ • 



The first segment of the right exopodite with 

 hyaline appendage. 

 Appendage at the inner distal angle, end.opo- 

 dite about equals the first segment of the 



exopodite, signicauda — p. ^5 o>» 



Appendage on inner distal half, quadrangular 

 in form, endopodite much shorter than the 



first segment of the exopodite, siciloides - j5» ' '^■^ O • 



The first segment of the right exopodite with 

 a transverse ridge, second segment with 

 oblique ridge and hyaline process near the 

 outer margi-a purpureus - 10' •" 'es » 



ANALYTICAL KEY TO THE ^'Or.TII AMERICAN SPECIES OF DIAPTO- 

 MUS BASED ON THE CHARACTEES OF THE FEMALE. 



The endopodites of the fifth feet are shorter than the 

 first segments of the exopodites. 

 The first antennae do not reach the end of the furca, 

 The endopodites are one-segmented. 



The exopodites are two-segmented, the fifth 

 cephalothoracic segment has a dorsal 

 pnocess, the first abdominal segment is 

 asymmetrical, its distal end being ex- 

 panded to the right, Trybomi 



The exopodites are three-segmented, there is no 



dorsal process, the abdomen is symmetrical piirpureits 



The fifth cephalothoracic segment has a dorsal 

 process, the first attdominal segment is asym- 



