FAMILY EMYSAURID&. 27 
ORDER II. SAURIA. 
Body long, cylindrical, covered with scales varying in size, or with small scaly granulations. 
Extrematies four. Tail usually very long, thick at the base. Mouth not capable of dila- 
tation, armed with teeth. Oviparous. Carnivorous. 
This order comprises about three hundred species, but as they are for the most part inha- 
bitants of the torrid zone, we have but twelve living and four fossil species in the United 
States. The State of New-York has but two living representatives of this order. 
(EXTRA-LIMITAL.) 
FAMILY EMYSAURID. 
Body lizard-shaped, large. Body furnished with large bony plates, often carinated, and forming two 
elevated crests on the tail. Sides of the body with small scales; beneath square, slender, smooth, 
Feet palmate. Head large, often elongated. Fluviatile. Carnivorous. 
This family corresponds with the order Loricata of Merrem and Fitzinger, and Emydosaurus 
of Blainville. It appears to be a link connecting the Chelonide with the order Sawria: it con- 
tains many extinct species. 
Genus ALLIGATOR, Cuvier. Nostrils separated by a bony partition; forehead divided by a short pro- 
minent carina. Four large tubercles on the neck, arranged in rows on each side of the vertebral 
line. Muzzle elongated, broad and obtuse. Teeth unequal. Feet semipalmated, and without 
indentation. 
A. mississippiensis. (Am. Tr. N.S. Vol. 2, p. 216. Hoxsroox, Vol. 2, pl. 7.) Dark ash brown 
above; lighter beneath. Four carinate plates on the neck, disposed in a square. 
Genus Crocopitus, Cuvier. Muzzle oblong, depressed. Teeth unequal; the fourth passing into 
grooves, and not into notches, in the upper jaw. Feet palmated. 
We have no living representative of this genus in the United States. Dr. Harlan has described 
and figured, in the Journal of the Academy of Natural Sciences, Vol. 4, p. 15, pl. 1, a fossil species 
from the greensand of New-Jersey. 
C. macrorhyncus. Jaw excessively thick. 'T'eeth thick, short and blunt. 
Genus Gaviauis, Cuvier. Head produced into an elongated snout. Teeth subequal, the fourth passing 
into grooves, and not into holes, in the upper jaw. Hind feet palmated to the end of the toe, and 
indented at the external edge. T'wo large holes in the cranium behind the eyes, which may be 
perceived through the skin. 
This group has no living representative in the United States. I have described, in the Annals of 
the Lyceum, Vol. 3, a portion of a fossil species from New-Jersey. 
