NATURAL SCIENCES OF PHILADELPHIA. 65 



superior antocnlar ; the frontal is long, presenting a nearly straigbt margin an- 

 teriorly, its sides scarcely incurvated, its posterior angle acute, passing a con- 

 siderable distance beyond the supra-oculars ; the supra-oculars are five-sided ; 

 they do not project over the eye ; the nostrils are between two plates, their 

 superior maroin in contact with the internasal, the posterior margin of the 

 second with the frenal, its postero-superior with the prefrontals ; the frenal is 

 obloDg, more or less quadrilateral, or rather pentangular, about twice as long 

 as broad ; there is one large antocnlar of singular shape, five-sided, larger above, 

 the surface by which it is in contact with the prefrontal, convex, the postero- 

 superior by which it is in contact with the supra-ocular and the frontal concave, 

 as well as the anterior and posterior margins ; there are two post-oculars, the 

 first somewhat quadrangular in shape, the inferior five-sided; the rostral is 

 broader than high, its latero-superior margins excavated, with an acute angle 

 above, its inferior margin also excavated, its lateral margins rounded ; there 

 are eight supra-labials, no two of them are precisely alike in shape ; the second 

 is higher than the first, and is quite narrow above ; the third is quite large, four- 

 sided, about as broad as long, the fourth smaller than the third, the firth five- 

 sided, the eye resting upon the upper margin of the fourth and fifth, which are 

 excavated to receive it; the sixth also pentangular, but higher than the fifth; 

 the seventh also pentangular, but in a different manner, and broader than the 

 last ; the eighth also pentangular, but broader than either the sixth or the 

 seventh, with a more obtuse angle above, and its summit lower than that of 

 either of the two last mentioned plates ; the middle labial is long, having an 

 acute angle posteriorly, broad in front ; the accessory labials are also long, and 

 pointed behind, the anterior geneials longer and more developed than the pos- 

 terior ; there are seven inferior labials; two parallel rows of large plates upon 

 the temples ; superior maxillary teeth of nearly equal size and moderately 

 curved, except the five anterior, which are longer, more robust, and more 

 strongly incurvated ; anterior inferior maxillary teeth longer than the others; 

 palatine and pterygoid teeth in two long rows, not straight, but slightly curved 

 anteriorly, presenting an ovoid interspace posteriorly ; tongue enclosed in a 

 sheath, with two slender pointed filaments in front ; ne;k not so 'thick as poste- 

 rior part of head ; body moderately robust, becoming more slender toward the 

 tail, which is of moderate length and tapering, but not pointed at its extremity : 

 the flanks present no remarkable angularity ; the scales are smooth, lanceolate 

 and narrow anteriorly, broader posteriorly ; there are 27 rows at the middle of 

 the body, 25 near the neck, 20 near the tail, upon which there are from 6 to 15 

 rows. 



Abdom. scut. 235 ; 1 single preanal ; 58 sub-caud. urostega, which are in a 

 double row. 



Coloration. Uniformly brown above upon the neck, body and tail, with two 

 vittae on each side of the head, as above described; chin, throat and neck white; 

 abdomen and under part of tail white, with dark colored maculse. 



DimeriHions. Length of head 1 inch ; greatest breadth 7 lines ; length of body 

 2 feet 2 inches 10 lines ; length of tail 4| inches. Total length 2 feet 8 inches 

 7 lines ; circumference 1 inch lOi lines. 



Ilahitat. Isle de Los. One specimen presented by Dr. Burtt, U. S. N. 



We have in the collection of Dr. Ford three specimens of a serpent formerly 

 described in the Proceedings under the name Caelopeltis virgata, but which is a 

 species of Boedon, and although allied to the species above described, differs 

 from it in the following particulars : The largest of the specimens is considera- 

 bly smaller than quadrivittatum ; the head is shorter and more obtuse ante- 

 riorly ; the temples more protuberant ; the frontal is more narrow ante- 

 riorly, less acute posteriorly ; the superior labials resemble those of quadri- 

 vittatum sufficiently, but there is a difference in t^e form of the frenal and ant- 

 ocular plate ; there is also but a single row of temporals, with a single large 

 one situated between the parietal and the three plates constituting this row; 



1857.] 



