PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM 



SMITHSONIAN INSTITUTION 



U. S. NATIONAL MUSEUM 



Vol. 108 Washington : 1958 No. 3392 



BRANCHINECTA CORNIGERA,A NEW SPECIES OF ANOSTRA- 

 CAN PHYLLOPOD FROM THE STATE OF WASHINGTON 



By James E. Lynch ^ 



The faii'y shrimp described below has been repeatedly collected 

 by the writer since 1935 from numerous ephemeral fresh-water ponds 

 in eastern Washington. The data in the specific diagnosis are based 

 on measurements of ten apparently full-grown individuals of each sex. 

 The specific name, cornigera, refers to the dorsolateral protuberances 

 on the head of the female, which remind one of incipient horns. 



Genus Branchinecta Yerrill, 1369 

 Branchinecta cornigera, new species 



Specific diagnosis: Male: Total length, from front to end of 

 shaft of cercopods, 29 (25-36.5) mm. Average ratio of length of 

 head and thorax to genital segments, abdomen, and cercopods 1 :L3. 

 Nuchal organ transversely oblong with rounded corners on top of 

 head. Compound eye in lateral view slightly flattened dorsoventrally, 

 0.9 (0.75-L05) mm. by 1 (0.95-1.2) mm. Antennule 2.6 (2-3) mm. 

 long, terminated by three setae and eight aesthetascs. Antenna 

 biarticulate, 7 (6-8) mm. long, extending back to the level of the fifth 

 or sixth thoracic segment if flexed posteriorly. Proximal article 4.5 



' School of Fisheries, University of Washington, Seattle, Wash. 



25 



446274—58 



