C'ROCODILIANS, LIZARDS, AND SNAKES. 



1197 



only separated from prenasal below the nostril, and from preocular by 

 a large loreal. Three rows of scales below orbit. Scales on top of 

 muzzle smooth, four on each side larger than the others, two bordering 

 the nasals above, ai)d two smaller ones bordering the superciliary in 

 front. Scales between superciliaries small, in five rows. Those behind 

 them and on the cheek keeled. External border of the superciliary 

 plate produced, sometimes (;onsiderably to an obtuse apex, which is 

 grooved longitudinally below. Scales of the body strongly keeled, 

 except the two inferior rows, which are smooth. 



General color light yellowish or brownish gray above, dirty white 

 below. The upper surface is crossed by a median series of transverse 

 brown hexagons, the color marked with numerous black punctulations. 

 Opposite the lateral apices of these, on the fourth row of scales, is a 

 small spot of the same color, and between these, on the first and sec- 

 ond rows, and the end of the adjacent gastrostege is a rather larger 



Fig. 347. 

 Crotai.us cerastes Hallowell, 



Cat. No. isaia, U.S.N. M. 



dusky spot. None of these spots have dark or light borders except the 

 median series, which are narrowly black edged anteriorly and poste- 

 riorly on the middle part. The dorsal bands increase in relative trans- 

 verse diameter on the posterior part of the body, but it is only on the tail, 

 and a part of the body of equal length anterior to it that they extend, 

 that they are united with the lateral spots. The extremities of the gas- 

 trosteges are shaded oi)posite the lateral and median spots, but tlu-y 

 are elsewhere unspotted. The head is in the specimens in alcohol with- 

 out markings on the pale ground color, excepting a dusky postorbital 

 band, which passes above the rictus of the mouth. The space anterior 

 to it, and below the eye, as far as the maxillary fossa, is very light 

 colored, probably yellow in life. The superior border of the postorbital 

 band is not defined; the inferior border is marked with some small 

 black spots. 



Cat. No. 8923; rows of scales, 21; upper labials, 12; gastrosteges, 1-42; urosteges, 

 24; total length, 485 mm. ; tail, 57 mm. ; rattle, 15 mm. 



