﻿68 PROCEEDmGS OF THE NATIONAL MUSEUM vol. lOo 



with a prominent flange ending at the anterior end of the ventral 

 margin in a small well-marked incisure. Ventral margin slightly 

 convex. Sm'face of valves smooth and sparsely covered with hairs. 

 Width greater than half the length when seen from above. Anterior 

 end slightly pointed, posterior end rounded from above. Furca 

 almost straight with rather weakly developed claws, which are slightly 

 bent. The length of the terminal claw is about equal to half that of 

 the dorsal margin of the ramus. The subterminal claw is about half 

 the length of the terminal. Terminal seta one-fom-th the length of 

 terminal claw. Length 2.68 mm.; height 1.66 mm. 



Male: Unknown, 



Material examined. — A large number of females of this species were 

 found in a collection from a reservoir near Porto Alegre (May) by 

 Dr. Kleerekoper. 



Reported distribution. — Argentina (Sars, 1901). 



CHLAMYDOTHECA UNISPINOSA (Baird) 



Figure 13, j 



Cypris unispinosa Baird, Ann. Mag. Nat. Hist., ser. 3, vol. 10, p. 3, 1862. 

 Cypris perelegans Herrick, Mem. Denison Sci. Assoc, vol. 1, No. 1, p. 27, 1887. 

 Chlamydotheca unispinosa Furtos, Carnegie Inst. Washington Publ. No. 457, 

 p. 96, 1936. 



Specific characters — Female: Elongated, with dorsal and ventral 

 margins nearly parallel. Height almost half the length; highest in 

 posterior region. Both extremities broadly rounded, the posterior 

 more so than the anterior. Anterior end of each valve with a mod- 

 erately developed flange. Eight valve with a spinelike protuberance 

 at the posterior ventral corner of the posterior flange. Natatory setae 

 of the second antennae do not extend to the tips of the terminal claws. 

 Terminal claw of second leg stout, curved, and smooth. Furcal 

 ramus straight and rather slender. Dorsal margin with four series of 

 short hairs. Dorsal seta two-thirds as long as subterminal claw and 

 removed from the base of the subterminal claw by twice the thick- 

 ness of the ramus. Terminal seta two-sevenths the length of the 

 terminal claw. Subterminal claw much smaller than the terminal. 

 Length 4.80 mm.; height 2.30 mm. 



Male: Smaller than the female but otherwise similar. (No males 

 were found in these collections but they are well known from other 

 regions.) 



Material examined. — One female was found in a collection made by 

 Dr. Kleerekoper (October) from a lakelet in the state of Rio de Janeiro. 



Recorded distribution. — Brazil (Klie, 1939); "Sandwich Islands" 

 (Bau-d, 1862); Jamaica (Herrick, 1887); Yucatdn (Furtos, 1936); 

 Illinois (Evenson, 1942); Ohio (Hoff, 1944); Louisiana, Maryland 

 (Tressler, 1947). 



