42 BULLETIN 138^ UNITED STATES NATIONAL MUSEUM 



the right dactjdus (pi. 12, fig. 2) is almost black, its inner surface 

 is visible, a deeply impressed line is parallel and close to the upper 

 margin ; lower down there is a broader groove on the proximal half ; 

 a huge, blunt, subconical basal tooth is directed obliquely inward, 

 dowuAvard and backward; remaining teeth unequal, the first and 

 third from the basal tooth being the largest; the dactylus graduall}' 

 narrows and curves well down at the extremity. The merus of the 

 ambulatory legs narrows rapidly at the proximal end and gradually 

 at the distal end. 



Measurements. — Male holotype, length to median sinus of front 

 22.8 mm., width at level of fourth (next to the posterior) tooth 

 29 mm., fronto-orbital width 15.9 mm., width of front 7.9 mm., 

 length of merus of an a'mbulatory (perhaps third) leg 19.8 mm., 

 length of dactylus of major cheliped 11.8 mm. 



Occurrence. — California : 21/^ Iniles south of the mouth of Soledad 

 Valley in the sea cliif ; on the La Jolla topographic sheet, due west 

 of half way between the "p" and "u" in Pueblo (south of the 

 mouth of Soledad Valley) in sea cliff facing ocean. Eocene series. 

 Holotype in University of California. 



Genus BRANCHIOPLAX Rathbun 



BrancMoplax Rathbun, Amer. Journ. Sci., vol. 41, 1916, p. 344 ; tji^e, 

 B. washingtoniana Rathbun. 



Carapace a little broader than long; anterior margin arcuate. 

 Orbits of moderate size, broadly oval, looking straight forward; 

 eyes stout, filling orbits. Antero-lateral margins dentate, shorter 

 than postero-lateral margins which are moderately convergent wdth 

 the posterior angles rounded. Front not emarginate. Regions well 

 defined, branchial regions swollen dorsally and approximate. Cheli- 

 peds unequal, of moderate length, carpus not much broader than 

 long, manus high. Related to Eua^ate de Haan ; ^^ type E. crenata de 

 Haan, a Japanese species. 



Contains only one species. 



BRANCHIOPLAX WASHINGTONIANA Rathbun 



Plate 9, fig. 7 



Branchioplax washingtoniana Rathbun, Amer. Journ. Sci., vol. 41, 1916, p. 

 345, 1 text-fig. 



Description. — Surface of cai'apace everywhere granulate, the 

 granules running larger and higher toAvard the margins and espe- 

 cially on the postero-lateral slope. The depressions in the center 

 of the carapace on either side of the gastro-cardiac area are deep. 



>3 Fauna Japon., Crust., 183.5, p. 36. 



