OPH1DIA CROTALIDAE CKOTALUS SCOTULATUS. 533 



" aa. Rattle paralldogrammic : 



" C.molossus, BairdandGirard. 2 9 rows of scales; 1H labials, 

 separated by 5 rows from orbit: brownish sulphur above, with 

 small, transverse, reddish, dorsal rhombs, the angles produced 

 as lateral bands ; no longitudinal bands on neck ; tail black. 

 Arizona and New Mexico. 



" II. Nasal plates distinct ; muzzle with small plates or numerous scales above : 

 " a. Muzzle ivitli 2 marginal shields above each canthus rostralis : 

 u b. An elevated, narrow, cuneiform rostral:* 



" C. polystictus, Cope. Scales 27 rows; superior labials 14, 

 separated from orbit by 2 rows : gray-brown, with 7 longitudinal 

 rows of brown spots ; top of head variegated. Mexico. 



"C. triseriatus, Wagler. Scales 23 rows; 2 pairs of large 

 scales on top of muzzle ; 6 rows between orbits : yellowish, with 

 a dorsal series of subround brown spots. Mexico. 



" C. confluentus, Say. Scales 25-7 ? (9) rows ; labials 15 

 to 18, separated from orbit by 4 rows; 6 to 10 rows between 

 superciliaries : yellow line from superciliaries above angle of 

 mouth ; a median dorsal row of brown spots, emarginate before 

 and behind, with alternating lateral series. Central and South- 

 west North America. 



" C. lucifer, Baird and Girard. Scales 25-7 ; labials 15- 

 16, with 4 rows above them: numerous subround, blackish, 

 dorsal spots, separated by narrow yellow lines ; a light band 

 from supercilia above angle of mouth. Pacific Region of North 

 America, Arizona. 



" C. scutulatiis, Kennicott. Scales 25 rows; superior labials 

 16; 3 or 4 rows interorbital scales, bounded in front by .two 

 shields : yellow stripe from eyebi'ow above rictus oris : yellowish 

 brown, with a dorsal series of truncate, brown, yellow edged 

 rhombs ; tail black ringed. Arizona. 



"NoTE. Mr. Ilenshaw informs me he killed several serpents 



* Professor Cope states that the former division of the species based on the acuminate or parallolo- 

 giuimnir form of the rattle must lie abandoned, as several of them with acuminate rattle exhibit a 

 parallelogrammic one when they reach a largo size. 



