A NEW SPECIES OF AMPHIPOD CEUSTACEAN (ACAN- 

 THONOTOZOMATIDAE) FKOM CALIFORNIA, AND 

 NOTES ON EUEYSTHEUS TENUICOENIS 



By Clarence R. Shoemaker 



Assistant Curator, Division of Marine Invertebrates, 

 United States National Museum 



In the course of a study of some amphipods recently sent to the 

 United States National Museum for identification by the Pacific 

 Biological Laboratories, of Pacific Grove, Calif., two specimens were 

 noticed which represent a new species. This I have named 

 Panoploea rickettsi for E. F. Ricketts, director of the Pacific Bio- 

 logical Laboratories. The genus Panoploea is now recorded for the 

 first time from the west coast of America. 



Eurystheus tenuicorriis was described by Prof. S. J. Holmes in 1904 

 from a single specimen taken in Puget Sound, but has not been 

 recorded by anyone since then. A number of specimens belonging to 

 the genus Eurystheus were noted among some amphipod material 

 received from several localities in southern California. Upon de- 

 tailed examination, I concluded that these specimens belonged with 

 Holmes's species Eurystheus tenuicornis, though the old and very 

 mature males exhibited some characters which were not possessed 

 by his specimen. These characters will be discussed under Eur'ys- 

 theus tenuicornis (Holmes) in the body of this paper. 



PANOPLOEA RICKETTSI, new species 



Figures 1-2 



Description. — Head, rostrum very long and narrow, front margin 

 with very shallow angle just below the eye, lower front corner bearing 

 two sharply pointed processes. Eye rather large, reniform, colorless 

 in the alcoholic specimens. Antenna 1 a little longer than 2, first 

 joint twice as wide and long as second, which is one-third longer than 

 the third, flagellum nearly twice as long as peduncle and composed 

 of about 13 joints. Antenna 2, fifth joint longer than fourth, 

 flagellum a little longer than peduncle and composed of about 20 

 joints. Mouth parts all elongate and projecting prominently below 



iNo, 2861.— Proceedings U. S. National Museum, Vol. 78, Art. 18. 

 23910—31 1 



