1854.] 95 



The total length of Say's Ameiva tesselata is 1 foot, tail 8J inches, in 

 this respect corresponding very well with the above, but none of the specimens 

 present the tesselated appearance described by Say, the ' transverse lines 

 dividing the whole surface in a tesselated manner." 



Eumeces, Wiegmann, 



Sp. char. Two supero-nasals contiguous ; internasal much more extended in 

 the lateral than antero-posterior direction, its internal margins in contact with 

 the anterior frenal ; two fronto-nasal, contiguous, lateral border in contact with 

 the posterior frenal ; frontal hexagonal, elongated, broader anteriorly ; fronto- 

 parietal rhomboidal, placed obliquely ; inter-parietal broad, with an acute angle 

 in front, passing in between the fronto-parietals ; parietals oblong, quadrilateral ; 

 four supra-orbitals ; a small naso-frenal : an anterior and posterior frenal, the 

 latter much larger ; twelve rows of smooth hexagonal scales upon the back, be- 

 ginning with those marked by the lateral vitta. 



Color. Shining black or brown above, with four bluish vittae, the two in- 

 ternal broader than the others, commencing about midway upon the sides of the 

 head immediately over the eyes, and extending along the back and terminating 

 upon the tail ; the lateral ones commence at the anterior margin of the orbit, 

 and passing beneath it, extend upon the sides and are lost upon the tail ; chin 

 and throat whitish ; abdomen and under part of tail slate color ; under surface of 

 extremities whitish. 



Dimensions. Length of head f inch ; breadth \ inch ; length of body and tail 

 4? inches; of tail 2 3-8ths inches; of anterior extremities inch; of posterior 

 | inch. 



Habitat. Lower California, near Mohave River, and in San Bernardino Valley. 



OPHIDIANS. 



Rhinostoma occipitale, nob. 



Char. Teeth of equal length, posterior ones not channelled ; head depressed, 

 eyes small ; a rostral, two anterior and two posterior frontals; one anterior and 

 two posterior oculars; a vertical ; two occipitals ; a small frenal ; nostrils in a 

 single plate ; seven superior labials, the eye resting on the third and fourth. 

 Abdom. scuta, 158 ; subcaud. 34. 



Coloration. Milk white above with 41 transverse black bands, including 

 seven upon tail and one upon posterior part of head ; six complete rings upon 

 tail ; throat and abdomen white ; under part of tail white, with transverse bands 

 continuous with those upon back of tail ; 15 rows of smooth quadrangular scales. 



Dimensions Length of head 4 lines, breadth 2 lines; of body 9 inches 9 

 lines; of tail, 1 inch 7 lines; total length, 9 inches. 



Hab. Mohave Desert. 



Gen. Remarks, This serpent resembles no other as yet figured in N. Ame- 

 rica, and is therefore easily recognized. In the genus Sonora of Prof. Baird and 

 Girard, there are, according to them, three postoculars, and two nasal plates on 

 each side with the nostril between them. In Sonora semiannulata there are 

 twenty-five transverse black bands upon the body, and six complete rings upon 

 the tail. The rings in Col. (Zacholus) zonatus of Blainville completely sur- 

 round the body. The nostrils, according to Blainville, open between two plates, 

 but Wagler has them each in a single plate, " in medio scutelli sitis," in his defi- 

 nition of Zacholus. Wagler, however, cites Col. Riccioli, Metaxa Serp. Rom. 

 as appearing to belong to this genus, " scheint als gattung zu gehoren," but C. 

 Bonaparte represents the nostrils as placed in the commissure between two scuta 

 M gli narici sono situate alia eommissura di duo scutelli nasali." Blainville 

 represents two black half rings upon the head. Zacholus zonatus is probably 

 allied to Coronella balteata. 



Crotalus cerastes, nob. 

 Sp. Char. Head covered with polygonal tubercles, larger in front, the latter 

 in three rows; two small quadrangular plates on each side, between the nostril 

 and the vertical rostral ; two quadrangular internasals ; external border of supra- 



