418 



S AURIA. 



now before us, a prepared skin, about the size of A. muricatus. It is 

 of the female sex, too, and thus compares well with the latter species. 



The scales of the upper surface of the head present no material 

 differences ; they are irregularly disposed upon longitudinal series, 

 somewhat larger upon the fronto-nasal region, subrhombic, or lanceo- 

 lated, and strongly keeled ; the occipital plate being very small. The 

 supraocular ridge and the position of the nostril immediately beneath 

 it, at equal distance between the anterior rim of the eye and the apex 

 of the snout or muzzle, are equally similar. The scales under the 

 head, on the other hand, are larger, being moderate in size, subequal, 

 subrhombic, slightly carinated, provided with an acute point at their 

 posterior angle. The subgular fold is simple also. The nape and 

 dorsal region of the body exhibit a very slight ridge, amounting to 

 a mere keel on the middle row of scales, which are very slightly 

 raised above the surface. The dorsal scales themselves are nearly 

 equal, well developed, rounded upon their posterior margin, slightly 

 keeled, disposed upon longitudinal series along the middle region of 

 the back ; towards the sides, they diminish somewhat in size, the 

 carination itself becoming very obsolete ; upon the abdominal region, 

 they appear nearly smooth, equal in size to those of the sides, and 

 obscurely disposed upon longitudinal series. The tail is subconical, 

 slightly depressed at the base, conical, and tapering into a point; it is 

 a little more than twice the length of the body and head together : 

 therefore, proportionally shorter than in A. rmiricaius. The scales of 

 its upper surface resemble, in size and shape, those of the dorsal region, 

 a few of the middle series being carinated, and that very slightly ; be- 

 neath, they are a good deal smaller than on the abdomen, and nearly 

 smooth also. The scales of the upper and lower surface of the limbs 

 resemble those of the back and belly, bearing the same relation to 

 them as is usually the case in the species of this genus, differing, in 

 the present species, from those of the preceding ones, by the same 

 general features as just referred to. 



The ground color is yellowish-olive. The upper surface of the head 

 and neck is dark brown. Five transverse, dark brown, undefined 

 blotches exist along the upper region of the body, making it appear 

 as though entirely brown, with yellow spots along the back, which 

 yellow spots are simply areas of the ground color not occupied by 

 the dark blotches. The flanks are clouded with brownish, fenes- 

 trated, or reticulated lines. On the sides of the neck is a double jet- 



