1852.] 179 
Dimensions of largest specimen. Length of head 1 inch 6$ lines; greatest 
breadth 9 lines; length of body 3 ft. 5 in. 7 lines ; j of tail 9 inches (mutilated ;) 
greatest circumference 3 inches 2 lines. 
Remarks. The animal above described differs 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, 1 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 Leconte, 
who resided a long time in Georgia, informs me that he also has seen but one. 
The present speeies, 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 
Dendyophis; in flavi-gularis they are broader, and many of them distinctly 
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 deseribes 
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 43 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 toend of the longest of the five toes 64 lines. 
Habitat. New Mexico. 
- HOMOLOSAURUS, 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 tail with smooth quadrangular scales ; 
external openings to the ears; throat folded; femoral pores; tail but little 
longer than the body; body and extremities slender. 
HomonosauRUS 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- 
