18 BULLETIN 97, UNITED STATES NATIONAL MUSEUM. 



TRIZOCARCINUS DENTATUS (Rathbnn). 1 

 Plate 1. 



Carcinoplax dcntattis RATHBUN, Proc. U. S. Nat. Mus., vol. 16, 1893, p. 243, 

 (type-locality, Gulf of California, lat. 29 40' 00" N. ; long. 112 57 r 

 00" W., 7G fathoms; holotype, male, Cat. No. 17462, U.S.N.M.). 



Trizocarcinus dcntatus RATIIBUN, Proc. U. S. Nat. Mus., vol. 47, 1914, p. 117 r 

 text-fig. 1, pi. 1. 



Diagnosis. A. pterygostomian stridulating ridge. Merus of 

 maxillipeds not broader than long. Segments of male abdomen 

 free; third segment reaching coxae. 



Description. Carapace about four-fifths as long as broad; pos- 

 terior median portion almost level and bordered by a blunt ridge 



from which the anterior and lateral por- 

 tions slope downward. Cardiac and 

 inesogastric regions in part demarcated. 

 Surface short-hairy, unequally granulate. 

 Front bimarginate, deeply grooved; 

 inner angle of orbit a subacute tooth. 

 Three flattened, upturned, pointed and 

 subequal antero-lateral teeth. Margins of 

 j teeth and orbit denticulate. Postero- 

 FIO. 3. TmzocARciNus DEXTA- lateral margins subparallel. Pterygosto- 



HOLOTYPE, SHOWING Simon- striae. A short complementary ridge ex- 



PB ' x ists on the lower proximal margin of the 



inner surface of the arm, and is crossed obliquely by 10 or 11 striae. 



Chelipeds granulate, outer face of carpus and chela clothed with 

 long hair except tips of fingers. An upper marginal spine on merus 

 at distal third; a lower subterminal spine. Inner spine of carpus 

 curved upward. Chelae flattened, margins serrulate ; fingers irregu- 

 larly toothed, not gaping. Inner surface of propodus with a deeply 

 concave surface below. 



Legs long and narrow; last three joints long, hairy, margins 

 granulate. 



Third segment of male abdomen the widest, first and second seg- 

 ments subequal in width, exposing the sternum. 



Measurements. Male holotype, length of carapace 14, width of 

 same 18 mm. 



Range. Gulf of California ; 30 to 76 fathoms. 



Material examined. 



Gulf of California, off Cape Lobos, Mexico: Lat. 29 40' 00" N.; 

 long. 112 57' 00" W.; 76 fathoms; gn. M.; temp. 59 F.; Mar. 24, 



1 The parenthesis about an author's name after a species name indicates that the 

 species was originally placed in a different genus. 



