58 BULLETIN 138, UNITED STATES NATIONAL MUSEUM 



orbit. Orbital margin crenulate; orbit small, as customar}^ in the 

 genus. Antero-lateral border inclined u]3ward. The ends of all 

 the lateral teeth are broken; the first tooth or orbital angle is not 

 prominent and is fused with the second which is probably a shallow 

 lobe ; the third, fourth, and fifth are subequal. Postero-lateral mar- 

 gins a little longer than antero-lateral, convergent ; posterior margin 

 sinuous. 



The carpus of the cheliped has a deep groove across the distal end ; 

 the inner tooth is short. 



Measurements. — Holotype, length of carapace 20.5 mm., width at 

 sinus in front of last lateral tooth 24.7 mm., fronto-orbital width 17 

 mm., width of front 9.1 mm. 



Occurrence. — Alaska: Just below the lower seepage on Pearl 

 Creek, on Pearl Creek oil claim No. 11; Nichowak District; Oligo- 

 cene series; carapace and carpus of left cheliped of one specimen. 

 Type in* University of California. 



Relation. — ^This species has much in common with L. heJlus,-^ a 

 species now living on the Pacific coast from Prince William Sound, 

 Alaska, to Long Beach, California. Its narrow part of the meso- 

 gastric region is not constricted but tapers gradually to a point, the 

 hepatic ridge is less pronounced and the branchial region is flat 

 where in the other it is symmetrically swollen. 



Genus CYCLOXANTHOPS Rathbun ] 



Cycloxanthops Rathbun, Proc. Biol. Soc. Washington, vol. 11, 1897, p. 

 164 ; type, C sexdccinidentatus Milne Edwards and Lucas. 



Carapace broad, antero-lateral borders very long; front horizon- 

 tal, prominent, divided into two lamellar lobes; orbits small, external 

 angles inconspicuous. Palms elongate, fingers stout, tapering to a 

 point. 



Pleistocene; Recent. Not before found fossil. 



CYCLOXANTHOPS NOVEMDENTATUS (Lockington) 



Plate 1, figs. 15 and 16 



Xanthodes? novemdentatus Lockington, Proc. California Acad. Sci., vol. 7, 



1876 (1877), p. 32. 

 Cycloxanthops novemdentatus Schmitt, Univ. California Publ. Zool., vol. 



23, 1921, p. 239, pi. 37, fig. 7, text-fig. 142, and synonymy. 



Occurrence. — California: Rincon del Potrero, Santa Monica; 

 Pleistocene; 29 movable (pi. 1, fig. 15), 13 immovable fingers (pi. 

 1, fig. 16) ; Cat. No. 353371, U.S.N.M. 



'^° Xantho bella StinJpson. Ann. Lye. Nat. Hist. New York, vol. 7, 1860, p. 204, pi. 5, 

 fig. 2. 



