18 CROCODIILA. 
The type of this well-characterized species is a female 37 inches long, and had been 
placed by Dr. Gray as his Swanka scorpoides. 
10. Cinosternum cobanum, sp.n. (Tab. XVIII. fig. B.) 
Hab. Guaremaua, Coban (Salvin), Cahabon (Sarg). 
Shell moderately convex, with an obtuse vertebral keel. First vertebral scute a little 
broader than long. Hind lobe of the sternum attached to the fixed portion by a suture, 
the two rami of which distinctly converge towards the middle. Gular plate short, as 
long as the interpectoral suture, much broader than long. Axillary and inguinal in 
contact. Sternum without notch behind. Jaws uniform whitish. 
This species seems to represent C. leucostomum in Alta Vera Paz; although founded 
on only two specimens, of which the largest is not quite 2 inches long, the distinguishing 
characters are sufficiently well developed. The smaller specimen from Coban is figured. 
Order CROCODILIA. 
Sumichrast (Bull. Soc. Zool. France, v. 1880, p. 170) gives the following account of 
the occurrence, &c. of the two Crocodilians found in Central America :— 
« Whilst the indigenous Crocodile (C. pacificus) inhabits both salt and fresh waters, 
estuaries, rivers, and lakes, the Alligator or Huizizil * never inhabits running or brackish 
water, but only the bottom of shallow or muddy streams in plains or stagnant pools in 
woods. It lies in deep burrows along the banks under the submerged roots of the great 
trees. Its character is much more savage than that of the Crocodile, and when disturbed 
it leaves its lair and fearlessly attacks an enemy. ‘The Crocodile only rarely does this. 
The female defends her young bravely, whether against the attacks of the male, who 
never loses an opportunity of devouring them, or that of any other enemy. Crocodiles 
frequently live in numerous herds in the estuaries along the edge of the sea, while the 
Alligator’s habits are solitary and nocturnal. On finding itself captured it becomes 
furious, lashing out violently with its tail and giving vent to a sort of hollow threatening 
erunt, and though it never attains so large a size as the Crocodile is more difficult to 
take. The food consists of fish, crustacea, and aquatic insects, and I have frequently 
found its stomach full of sand, gravel, and water-plants. 
“The iris is of a greenish grey as in the Crocodile. Age does not make any great 
change in its form or the shape of its head.” 
* The word “ Huizizil” is of Aztec origin; among the ancient Mexicans it was applied to the Humming-bird. 
+ The largest individuals I have observed do not exceed 1°72 metre. 
