NEW SPECIES AND A NEW GENUS OF PARASITIC 



COPEPODS. 



By Charles Branch Wilson, 

 Department of Biology, State Normal School, West field, Massachusetts. 



The material for the present paper has been derived from a variety 

 of sources, which have been duly acknowledged under the separate 

 species. 



It includes not only true parasites, but also commensals or semipar- 

 a sites, whose relation to the animals with which they are associated 

 is not even yet fully understood. Five of the species are North Amer- 

 ican, one was obtained in Japan, one in the Hawaiian Islands, and 

 one in Jamaica. The types of the new species as well as all the 

 specimens herein mentioned are deposited in the National Museum. 



LEPEOPHTHEIRUS LONGIPES Wilson. 



Plate 1, figs. 1-5. 



Host and record of specimens. — Four adult females, five males, 

 and two immature females were obtained from the rock bass, Para- 

 labrax clathratus, at Crescent Bay, Catalina Island, California, by 

 Dr. A. B. Ulrey, of the University of Southern California. They 

 have been given Cat. No. 49779, U.S.N.M. The males and develop- 

 ment stages are new for this species and are here described for the 

 first time. 



Characters of immature female. — Carapace relatively enormous, 

 three times as long and four times as wide as the rest of the body; 

 free thorax (fourth) segment wider than the genital segment and 

 two-thirds as long; genital segment almost twice as wide as long, 

 with a pair of one- jointed legs at the posterior corners, which are 

 distinctly visible in dorsal view. 



Abdomen one- jointed, the same length as the genital segment and 

 half as wide ; anal laminae relatively large ; fourth legs, if straight- 

 ened backward, reaching beyond the center of the abdomen, but not 

 to its posterior margin. The chief points of difference between this 

 development stage and the mature adult are the size of the carapace 

 compared with the rest of the body, the relative length and width of 



Proceedings U. S. National Museum, Vol. 59-No. 2354. 



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27177— 21— Proc.N.M.vol.59 1 



