1852.] 179 



Dimensions of largest specimen. Length of head 1 inch 6J lines ; greatest 

 breadth 9 lines ; length of body 3 ft. 5 in. 7 lines ; of tail 9 inches (mutilated;) 

 greatest circumference 3 inches 2 lines. 



Remarks. The animal above described difiFers from the Psammophis flagelli- 

 formis, in being more robust, and in its coloration ; all the specimens brought 

 by Dr. Woodhouse being of a light brown or olive color above, and of a yellow 

 straw color beneath. The specimen of flagelliformis in the collection of the 

 Academy corresponds with the description of Prof. Holbrook, who makes the 

 following observations in regard to its color ; '* The superior surface of the head 

 and neck and nearly one half of the body, is raven black, gradually becoming 

 green on approaching the tail, which is of a very light brown or tawny color ; 

 the scales on the tail are rendered conspicuous by their dark margins. The 

 inferior surface of the neck and anterior part of the abdomen is bluish slate 

 color, the posterior part white clouded with brown ; some parts of the abdomen 

 white and shining, as well as the inferior surface of the tail. This snake, how- 

 ever, varies in color or rather in shade. Bartram has seen them of a cream 

 color, clay colored, and sometimes almost white, but always raven black near 

 the head." The Psammophis flagelliformis appears to be rare. Prof. Holbrook 

 having seen but one specimen during a seven years' search ; and Major Le Conte, 

 who resided a long time in Georgia, informs me that he also has seen but one. 

 The present species, according to Dr. Woodhouse, is very abundant where he 

 discovered it namely, in the sandy region reaching from the frontiers of Texas 

 to the Creek Territory, and designated by a strip of timber extending across it. 

 The specimen under consideration appears also to differ from flagelliformis in 

 the form of the scales, the number of rows of which is the same in both species. 

 In flagelliformis they are more narrow and elongated, resembling the scales of 

 Dendrophis ; in flavi-gularis they are broader, and many of them distiactly 

 hexagonal. The tail is two and a half inches shorter than in flagelliformis, 

 but the body of flagelliformis is eight inches longer. Schlegel observes that 

 the serpents belonging to this genus may be considered as holding a middle place 

 between the terrestrial serpents and those which inhabit trees ; he describes 

 eight species, none of which belong to the United States. The present species, 

 however, is known to ascend trees with great agility, reaching their summits 

 with ease when attacked. 



ELGARIA, Gray. 



Elgaria marginata. 



Sp. Char. Head and upper part of body and tail olive colored; a few minute 

 points along the middle line of the back ; nine or ten transverse bars of black 

 along the sides ; the posterior margin bordered with white ; under surface 

 greenish olive, immaculate. 



Dimensions. Length of head 4| lines ; greatest breadth 2 lines ; length of 

 neck and body to vent 1 inch ; length of tail 1 inch (mutilated ;) length of an- 

 terior extremities to end of the longest of the five fingers 4^ lines ; length of 

 posterior extremities to end of the longest of the five toes 6^ lines. 



Habitat. New Mexico. 



HOMALOSAURUS, Hallowell. 



Gen. Char. Head depressed, covered above with polygonal scales ; nostrils 

 superior; occipital plate distinct; temples not swollen; marginal plates of the 

 upper jaw imbricate; upper surface of neck, body, and tail covered with granu- 

 lations ; abdomen and under surface of the tail with smooth quadrangular scales ; 

 external openings to the ears ; throat folded ; femoral pores ; tail but little 

 longer than the body ; body and entremities slender; 



HOMALOSAURUS VENTRALIS. 



Sp. Char. Head silvery white, with a tinge of yellow ; body above ash- 

 colored, thickly maculated with small white spots irregularly disposed ; trans- 

 verse dark colored bars upon the posterior extremities and base of tail ; abdo- 



28 



