46 



ciliated on the mesial aspect, setae strongly pectinate. Antennae ex- 

 tending to or beyond the end of the stylets, purple-tipped, 25-jointed. 

 The antepenult joint of the right male antenna with a curved hook. 

 The fifth foot of the female with very short inner ramus which is more 

 or less distinctly two-jointed or simply attenuated beyond the middle, 

 armed apically with two or more spines and setae. External branch 

 3-jointed, third segment obvious and armed with one long and one 

 shorter spine. Claw rather straight, armed for the middle third of its 

 concave aspect with sharp teeth. The right fifth foot of the male has, 

 on the outer ramus, a long sickle-shaped claw with few teeth or none, 

 it being nearly as long as the remainder of the leg. The penult joint 

 is long and bears a long thick spine which is slightly curved and may 

 be dentate and is affixed at a point of the segment one fourth its length 

 from the end. The basal joint of the outer ramus is very short and, 

 like the next following has a lateral hyaline plate. The inner ramus 

 is very short and 1-jointed. The second protopodite segment of the 

 left foot is nearly as long as that of the right, the inner ramus is 

 1-jointed and simply ciliate at the end. The apical segment of the 

 outer ramus is acute and bears a short, ciliated , conical process and 

 a minute spine apically as well as a ciliated internal lamina. The 

 preceding joint also has such a lamina or a patch of short spinules 

 upon a protuberance. 



Color pellucid, with purple upon the tips of the antennae and 

 caudal stylets. 



Length of female, 1*4 — 1-6 mm. 



Waters about Albuquerque New Mexico very abundant. 



Diaptomus iiovomexicamis n. sp. 

 (Figures 27—29.) 

 A species of moderate size, rather robust, with the greatest width 

 of the thorax near the middle. Last two thoracic segments distinct, 

 the last with two small spines. First abdominal segment very long, 

 much exceeding the remainder. Second segment short. Stylets about 

 as long as the preceding abdominal segment. Antennae reflexed 

 reach to the base or end of the stylets, 25-jointed. Antepenult 

 «egment of right male antenna with a hyaline lamina which does not 

 extend the entire length of the joint and ends in a rather short scar- 

 cely hooked process distad. The outer ramus of the fifth feet is ob- 

 viously three-jointed, the apical joint being small and armed with two 

 subequal spines. A small spine is inserted near the base of this joint. 

 The claw is curved and dentate near the apex. The inner ramus is as 

 long as the basal joint of the outer ramus, 1-jointed, and armed at 



