Marsh — North American Species of Diaptomus. 471 



sharply curved at the middle that the two parts make very 

 nearly a right angle with each other. Its length equals that of 

 the whole right foot. It is finely denticulate on the proximal 

 half of the inner margin. The endopodite is short, stout and 

 pointed, equaling in length the first segment of the exopodite. 

 It is setose at the tip. The left foot reaches beyond the middle 

 of the second segment of the right exopodite. The second 

 basal seg-ment is longer than broad, and nearly equals in length 

 the corresj)onding segment of the right foot. The lateral hair 

 is near the distal end. The first segment of the exopodite ii 

 twice as long as wide, and setose on the inner margin. The 

 second segment is spherical in form, setose on its inner margin, 

 and is terminated by a setose finger-like process and a slender 

 falciform spine. The endopodite is slender, equal in length 

 to the first segment of the exopodite, and setose at tip. 



Length of female, 1.5 mm. Length of male, 1.25 mm. 



Locality, temporary pools near Lincoln, jSTebraska. 



If D. albuquerquensis Sehacht is identical with D. saltil- 

 linus, this species is also found in Florida. The relationship 

 of D. albuquerquensis Sehacht to D. saltillinus is discussed un- 

 der D. albufjuerquensis. 



DIAPTOMUS ALBUQUERQUENSIS Hcrrick. 



Plate XXIV, figs. 4, 7-10. Plate XXV, fig. 1. 



1895. Diaptomus albuquerquensis Herrick, p. 45 ; figs. 16-26. 

 1895. Diaptomus albuquerquensis Herrick and Turner, p. 67; 



pi. VI, figs. 1-3 ; pi. VII, figs. 1-11. 

 1904. Diaptomus Lehmeri Pearse, p. 889; figs. 1-4. 



Of moderate size. The cephalothorax is broadest at ths mid- 

 dle. The first segment is about equal in length to the three 

 following. The last seg-ment in the female bears a blunt dorsal 

 tooth ; the segment is expanded laterally, each wing bearing 

 two rather prominent spines. 



The first abdominal segment of the female equals in length 

 the remainder of the abdomen and the f urea ; it is dilated lat- 



