SNAKES. 



83 



2. HETERODON NIGER. 



Vipera nigra, Catesby, Hist. Nat. Carol, pi. 44. Coluber caco- 

 daemon, Shaw, Gen. Zool. iii. pi. 102. Scytale niger, Daud. 

 Hist. Nat. Rept. v. p. 342 ; Harlan, Journ. Acad. Nat. Sc. Philad. 

 v. p. 367. Pelias niger, Merr. Tent. p. 149. Coluber thraso and 

 Scytalus niger, Harlan, Phys. and Med. Res. p. 120. Hetero- 

 don niger, Troost, Ann. Lye. Nat. Hist. New York, iii. p. 186 ; 

 Holbr. N. Amer. Herpet. iv. pi. 16. H. vipera, Fitz. Syst. Nat. 

 56. H. platyrbinos, var., Schley. Ess. ii. p. 100 ; Baird # Girard, 

 Catal. p. 55 ; Dum. fy Bibr. vii. p. 769. 



Scales keeled ; shields of head like in H. platyrhinos. Whok 

 body black above, without any spot ; slate-colour below. 



a. Adult : partly bleached. N.America. Old Collection as Hete- 

 rodon nigricans. 136 ventral plates. Perhaps only a variety 

 of H. platyrhinos. 



3. Heterodon catesbyi. 



Oxyrhina catesbyi, Gray in Brit. Mus. 1836. Heterodon 

 platyrhinos, var., Schley. Ess. pi. 3. f. 20-22. Heterodon sitnus, 

 Holbr. N. Amer. Herpet. iv. pi. 15. Heterodon simus and H. na- 

 sicus, Baird Sf Girard, Catal. p. 59, &c. Heterodon platyrhinos, 

 var., Dum. £f Bibr. vii. p. 7G7- Heterodon nasicus, Baird § 

 Girard in Marcy, Explor. of the Red River, pi. 4. 



Scales keeled ; behind the rostral an azygos shield, surrounded 

 by smaller scale-like shields ; orbit surrounded by similar shields ; 

 upper labials not in contact with the eye. Coloured like H. 

 platyrhinos. 



a. Adult: bleached. N.America. From Sir H.Sloane'sCollection. 



b. Adult. Texas. From Mr. Brandt's Collection. 



c. Nearly half-grown. North America. Presented by the College 



of Surgeons. 



d. Nearly half-grown. North America. Presented by the College 



of Surgeons. 



e. Half-grown. N. America. From Mr. Cuming's Collection. 



f. Young. N. America. Presented by the College of Surgeons. 



g. Adult. N.America. Presented by the College of Surgeons. 



Specimens b, e, f, belong to the variety H. nasicus. 



4. Heterodon d'orbignyi. 



Dum. <y- Bibr. vii. p. 77 L 2. 



Scales smooth; behind the rostral a small azygos shield, in 



