CROCODILIANS, LIZARDS, AND SNAKES. 

 These geuera are distributed as follows : 



957 



The genus yafrix is the water-snake form of all temperate regions 

 aud of tropical Asia. The Europeau X. nairix is terrestrial lor the 

 most part, but the North American and Indian species are very- 

 aquatic, diving to the bottom of the water to escape enemies on the 

 shore. The genus Eutienia., for the most part North American, includes 

 many species of terrestrial habits, and they are all often ibund far from 

 water. The E. saurita takes to the water if alarmed. A number of 

 North American genera are degenerate forms of Natricina^, which hav^e 

 adopted a terrestrial aud even a burrowing life like that of the Cala- 

 marinie. iSforeria is like a Natrix reduced in the lateral head plates 

 and with feeble jaws. Tropidoclonium is related in the same way to 

 EuUvnia. Haldea and AmpMardis have a more decidedly fusiform 

 character. HaMca displays the hypopophyses continued to the cau- 

 dal region, as in the other members of the subfamily. 



The African members of the family are few in number, as but one 

 species of Xatrix (N. mortuarlus) occurs there. 



NATRIX Laurenti. 



iV^a/rij^LAURENTi, Specimen Synopsis Reptilinm, 1768, p. 73. — Boxapaktk, FauLa 



Italica, 1840, pp. 172, 173. 

 Tropidonolm Kuhl, IsisvonOken, 1826, p. 205. — Boie, Isis von Oken, 1827, p. 518. — 



Wagler, Systenia, 1830, p. 179.— Schlegel, Ess. Phys. Serp., 1837, p. 296. — 



DuMERiL and Bibron, Erp. Go'n., VII, 1854, pp. .549-724. — GCxxnER, Cat. 



Col. Snakes Brit. Mas., 1858, p. 58. 

 Xerodia Baiud and Girakd, Cat. N. Amer. Kept., Pt. 1, Seri)ents, 1853, p. 38. 

 liefiin a BAUiDSbiul Giuard, Cat. N. Amer. Rept., Pt. 1, Serpents, 1853, p. 45. — Cope, 



Proc. Acad. Nat. Sti. Phila., 1862, p. 338; Bull. U. S. Nat. Mns., No. 32, 1887, 



p. 71. 



Teeth generally longer on the posterior than the anterior parts of 

 of the maxillary bone, ungrooved. Two internasal, two prefrontal, and 

 two nasal scuta; one loreal; parietals distinct. Anal plate divided. 

 Scales keeled ; scale-pits double. Gastrosteges well developed, not 

 angulated or keeled. 



This genus is widely distributed throughout the Northern Hemi- 

 sphere, embracing numerous species in North America and in Eurasia, 

 but is wanting on the Pacific district of the former. On the Ameri- 

 can continent a single species, N. rhombifer Hallowell, extends as far 



