THE SPIDER CRABS OF AMERICA 379 



setae, and some rows of long, stout setae on sternum and legs. Legs 

 with merus and carpus bicristate above, propodus unicristate, crests 

 divided into a few large lobes or teeth. These, as well as the lobes of 

 the chelipeds are each tipped with a cluster of setae. 



Measurements. — Male (46076), total length of carapace 16.8, width 

 18.3, length of horns 1.8 mm. Male, holotype, length 25.4, width 

 31.4 mm. (Stimpson). Female (Tepoca Bay), total length of car- 

 apace 27.3, width 32.8 mm. 



Range. — Gulf of California to Panama. 



Material examined. — 



Lower California; M. Diguet; 2 immature females (Paris Mus.). 



Tepoca Bay, Sonora, Mexico; April 15, 1921; Fred Baker, Cal. 

 Acad. Exped.; 2 females (Cal. Acad.). 



Pinacate Bay, Guaymas, Sonora, Mexico; Capt. C. M. P. Stone; 

 1 ovigerous female, paratype (331, M. C. Z.); described and figured 

 by A. MUne Edwards. 



Manzanillo, State of Colima, Mexico; on drifted pile; July 17, 

 1913; C. R. Orcutt; 1 male (46076). 



Pearl Islands, Bay of Panama, Panama; S. W. Garman; 1 male 

 (2039, M. C. Z.). 



Remarks. — -As Kingsley*® has remarked, of one of Lockington's 

 cotypes, the first lobe of the antero-lateral margin is narrower and 

 more slender than figured by Stimpson, his type being a larger speci- 

 men. 



Genus MITHRAX Latreille 



Mithrax Latreille, Regne Anim. de Cuvier, vol. 3, 1817, p. 23; type, M. 



hispidus (Herbst). 

 Trachonites Latreille, in Desmarest, Diet. Sci. Nat., vol. 28, 1823, p. 263; 



type, M. hispidus (Herbst). 

 Mithraculus White, List Crust. Brit. Mus., 1847, p. 7; type, M. coronatus 



White (part)=M. sculptus (Lamarck). 

 Nemausa A. Milne Edwards, Crust. R6g. Mex., 1875, p. 80; type, A^. 



spinipes (Bell). 



Carapace ovate or oblong-ovate, either broader than long or 

 slightly longer than broad. Antero-lateral margin bearing usually 

 four, sometimes three, spines or lobes behind the orbit; postero- 

 lateral margin sometimes having a spine or tubercle. The front has 

 two small rostral horns, either pointed or truncate, sometimes very 

 short, and beside them are other spines or prominences, either pre- 

 orbital or antennal. Orbital borders more or less spinous or tubercu- 

 lous. Antenna short; basal article wide, armed in front with two 

 or three spines or lobes; second article inserted outside the orbit, at 

 base of rostrum. Merus of outer maxillipeds wide and dilated 

 outwardly; exognath wide. Sternal plastron almost circular. 



«• Proc. Boston Soc. Nat. Hist., vol. 20, 1879, p. 146. 



