556 PROCEEDIISrGS OF THE NATIONAL MUSEUM vol.84 



of two articles. Proximal article cylindrical, slightly constricted 

 near the middle, 7.5 (6.5-9.0) mm in length. Terminal article blunt, 

 somewhat flattened and slightly curved inward, and twisted in such 

 a way that the broader diameter at the tip is at right angles to 

 the corresponding transverse axis at proximal end of the article. 

 Length of terminal article 5.2 (4.5-6.0) mm. Both articles of an- 

 tenna devoid of processes, tubercles, or denticulations, although both 

 l^resent considerable areas granulous with microscopic papillae. 

 Compound eyes small; peduncles 1.0-1.6 mm long; oval corneal por- 

 tion 0.60-0.71 mm in the longer (anteroposterior) axis. Median 

 ocellus present. Labrum truncated, bearing a blunt nasiform pro- 

 cess. Median border of endopodite bears heavily chitinized hooked 

 spines, with a triangular area of denticles on dorsolateral side. 

 Everted penes bear a spur near the base and two spinose lobes near 

 distal end. Cercopods 13.5 (10.3-16.3) mm in length, diverging, with 

 a row of plumose setae extending most of the length of cercopod 

 on ventrolateral side; similar, but longer, setae occurring dorsally 

 and medially in distal half only. 



Female: Total length from front to end of cercopods 86 (69-97) 

 mm. Antennule 5.5 (3.8-6.8) mm in length. Antenna 12.6 (7.8-15) 

 mm in length. Antenna of female composed of one article, tapering 

 gradually to a sharp point. Three-fourths of distance from cephalic 

 end to apex of antenna there is a slight swelling, distally to which 

 antenna presents a feeble sigmoid curve. Ovisac piriform, 11 (7-13) 

 mm in length, 6.2 (4.5-7.5) mm in transverse diameter at base, and 

 carrying 200 to 600 eggs. Females exceed males in all dimensions 

 except for lengths of antennules and antennae and diameter of eye 

 (diameter of cornea slightly smaller than that of male). Average 

 ratio of length of males to that of females is 1 : 1.36. Cercopods 18.6 

 (12.5-22.5) mm in length. 



Locality. — Temporary alkali ponds in the Upper Grand Coulee, 19 

 miles north of Coulee City, Grant County, Wash. 



Type specimens.— 'Rolotyr)^ (U.S.N.M. no. 72572) and paratypes 

 have been deposited in the United States National Museum. 



Description. — The color of living specimens was a translucent 

 white, with a mere suggestion of a bluish cast. The intestine in 

 freshly collected specimens was bright red, caused by a diet of red 

 Diaptomus sp. The ovaries were pale blue; eggs, when first dis- 

 charged into the ovisac, pale blue-green, turning yellow before being 

 laid. Cement glands in the ovisac were dark yellow to light brown. 



Both articles of the clasping antenna of the male are provided with 

 microscopic papillae, which are likely to be overlooked when the ani- 

 mals are studied with low magnifications. The inner and anterior 

 sides of the terminal half of the distal article are covered with small, 



