208 [December, 



the snout less pointed ; the neck also in fasciatus is much more contracted, and 

 the body and both anterior and posterior extremities are much less robust. In 

 addition to these distinguishing characteristics, sufficient of themselves to sepa- 

 rate the two animals, there exist in fasciatus seven or eight narrow transverse 

 bands of a bright vermilion color upon the back, which are not observed in the 

 other species. 



TROPIDONOTUS, Kuhl. 



Tropidondtus Woodhousii. 



Sp. Char. Head long, depressed, rounded in front; eyes projecting; neck 

 much contracted ; body thicker in the middle ; tail of moderate length ; scales 

 strongly carinated ; a series of transverse rhomboidal dark colored blotches 

 upon the back, less distinct near the tail, obsolete upon the anterior half of the 

 body; which is of an olive green color ; interstices between the blotches white ; 

 23 rows of scales. Abdominal scuta 150; sub-caudal 



Description. The head is quite large and much depressed, covered above with 

 nine plates ; of these the anterior frontal are pentangular, their posterior and 

 external angle being somewhat prolonged ; the posterior frontal are much 

 larger and irregularly quadrilateral ; the vertical is pentagonal, much 

 broader in front than posteriorly, its lateral margins being slightly hollowed ; 

 the supra-orbitar are oblong, pentagonal, broader behind than in front; the 

 occipital are very large, pentagonal : the rostral is broad and quadrilateral, 

 rounded above, excavated below ; the nostrils look upward and outward, and 

 are situated between two nasal plates ; there is one loral on each side which is 

 quadrilateral ; there are one anterior ocular and three posterior ocular plates ; 

 the former is quite large, and excavated anteriorly, so as to receive the 

 posterior margin of the loral ; there are two large temporal plates on each side 

 of the occipital; there are eight labials upon the margin of the upper jaw on 

 each side; of these the sixth and seventh are the largest ; the eyes are large and 

 projecting, the supraorbitars extending but slightly over the eye ; the 

 mental plate is small and triangular ; the anterior and posterior geneials are 

 quite long, the posterior somewhat more slender and larger than the anterior ; 

 the body is long, much thicker in the middle than at the extremities, covered 

 with twenty-three rows of strongly carinated scales ; the rows upon the sides 

 are much less strongly carinated than those upon the back ; the row nearest the 

 abdomen is the broadest. 



Color. Dusky olive upon the upper part of the head and back, becoming 

 darker upon the middle of the body, and toward the tail, presenting numerous 

 transverse dark colored bands, most distinct upon the posterior half of the body ; 

 these bands do not, as in Tropidonotus sipedon, extend as far as the abdomen; 

 they are bordered anteriorly and posteriorly with a strip of white ; chin, thorax 

 and neck straw color ; the abdominal scales are bordered anteriorly with black ; 

 tail, straw color, with indistinct bands of black along the borders of the scales. 



Dimensions. Length of head 1 inch 6 lines ; greatest breadth 9 lines ; length ; 

 of body 2 ft. 2 inches; of tail 5^ inches. Abdominal scuta 150; sub-caudal 44, 

 (tail broken off at extremity.) 



Habitat. Prairies near the Arkansas river. 



Remarks. The reptile above described resembles the Tropidonotus erythro- 

 gaster, in having the same number of rows of scales, there being 23 in each ; 

 and nearly the same number of abdominal plates, there being 148 in the erythro- 

 gaster and 149 in Woodhousii. The tail in the specimen of the latter species 

 having been mutilated, their number could not be accurately determined. The 

 coloration of the two animals, however, is very different, the white transverse 

 bands upon the back being very apparent in Woodhousii, but do not exist in 

 erythrogaster. They differ also greatly in size, Woodhousii being a much 

 smaller animal. Tropidonotus fasciatus has 140 abdominal plates and 42 pairs 

 of sub-caudal scales. The " body has singular oblong or triangular purplish 

 red spots on the flanks, which are insensibly lost about midway between the 

 abdomen and vertebral line." "In old animals the whole superior and lateral 

 surface becomes of a brownish color." Its circumference is five inches. 



