SAURIANS. 15 



lower ones entering into holes in the upper jaw, and not. into notches; 

 their feet are only semi-palmate and without emarginatioh. They have 

 hitherto only been certainly found in America. 



Croc, sclerops, Schn. ; Seb. I, civ, 10; Cuv. Ann. Mus. X, 1, 

 7, and 16 and 11, 3, (The Spectacle Alligator), so named from a 

 transverse ridge, which unites in front the salient borders of its 

 orbits, is the most common species in Guiana and Brazil. Its neck 

 is defended by four transverse bands of strong plates. The female 

 lays in the sand, covers her eggs with straw or leaves, and defends 

 them courageously*. 



Croc, lucius, Cuv. ; Caiman a museau cle brocket, Ann. Mus. X, 

 1, 8, and 15, and II, 4, (The Pike Alligator), so called from the 

 shape of its muzzle, is also distinguished by four principal plates on 

 its neck. It inhabits the southern parts of North America, forces 

 itself into the mud, and remains torpid in severe winters. The fe- 

 male deposits her eggs in alternate layers with beds of earth "j" («). 



their plantations. The word Alligator is used by the English and Dutch colonists in 

 the same sense. It is a corruption of the Portuguese word Lagarto, which is itself 

 derived from Lacerta. 



* There are also several sorts of Caimans or Alligators, which have this trans- 

 verse ridge front of the orbits, and which, like the Crocodiles, allied to the common 

 one, perhaps form distinct species, but difficult to characterize. 



Some of them have a shorter and more rounded muzzle; the transverse ridge con- 

 cave before, and extending to the cheek on each side. They have thirteen teeth on 

 each side above; their cranium is not widened behind; their body is green dotted, 

 and spotted with black, with black bands on the tail. 



Others have the same kind of head, and the same teeth, but their body is black, 

 with narrow bands that are yellowish, as in the Jacare noir, Spix, pi. iv. 



Others, again, have a muzzle less broad, and the concave ridge does not extend so 

 far; they have fifteen teeth, and their neck is more completely defended by plates; I 

 should willingly consider them as the Cr. fissipes of Spix, pi. iii. 



Finally, there are some with a still narrower muzzle, and the cranium somewhat 

 widened behind, whose transverse ridge is convex in front, and does not extend on 

 the cheek; the ridge of their dorsal plates is less salient, and the bands on their tail 

 are more faintly marked: can they be the Cr. punctulatus of Spix, pi. ii? That gen- 

 tleman, unfortunately, has not insisted upon the characters drawn from the trans- 

 verse ridge. 



f See, on this species, the paper of Dr. Harlan, Ac. of Nat. Sc. of Philad. IV, 

 242. — Add, the Caiman a paupieres osseuses (Croc, palbebrosus, Cuv.), Ann. Mus. X, 

 pi. 1, C and 7, and 11,2; and the Croc, trigonatus, Schn., Seb. I, cv, 3; or the Jacare- 

 tinga moschifer, Spix, pi. i. The whole thickness of the eye-lid, in this species, is 

 occupied by three osseous lamella?, of which, in other Crocodiles, there is scarcely a 

 vestige. 



IggT (a) Fossil remains of Crocodiles are found in the Secondary formations of 

 the south-east of Sussex, and in each of the series composing these formations, from 

 the Oolite to the Chalk, both included. The Tertiary deposits likewise contain them. 

 Some teeth found in Tilgate Forest, by Mr. Mantel], have all the essential charac- 

 ters of those of living Crocodiles, and they are calculated by that experienced geolo- 

 gist to have belonged to animals between twenty and thirty feet long. The fragments 

 of the bones of Crocodiles, in the possession of Mr. Mantell, are those of at least 

 two species, if not of four. They consist of teeth, scales, vertebrae, ribs, and other 

 bones. Teeth of fossil Crocodiles are also abundant in the Wealden formation, re- 

 sembling those of the Jura limestone, and those of the Gavials. — Eno. Ed. 



