MORPHOLOGY OF VENOMOUS SNAKES 9 



a peculiar tubercular carination and distinguishes this species from a very closely 

 allied Scolecophis atrocinctus. Size rather small. It inhabits a rocky, moun- 

 tainous region. Three species are known. 



Genus TAWTILLA Baird and Girard. 

 TantUla Baird and Girard, Cat. N. Amer. Rep., Pt. I, Serp., 1853, '3 1 ' 

 Homalocranium Duineril and Bibron, Mem. Acad. Sci., 1853, XXIII, 490. 



Posterior maxillary tooth grooved. Head depressed and continuous with neck- 

 No loreal. Eyes below medium size. Body subcylindrical, tail short. Scales 

 smooth. Subcaudal divided. Most of the species belonging to the genus are small, 

 have a pale brown body and a black head, and lead a secretive or burrowing life. 

 They inhabit especially the Central American, Mexican, and South American 

 districts and the southern portions of the United States. About 16 species com- 

 prise this genus. From the hygienic standpoint the TantUla are non-dangerous 

 poisonous snakes. 23 species are described by Boulenger. 

 TantUla coronata Baird and Girard. 



A yellow or white ring at base of head. Yellow ring followed by a broader ring 

 of black. South Carolina, Florida, and westward to Mississippi. 



TantUla eiseni Stejneger. 



Yellow ring followed in rear by black dots. California. 



TantUla nigriceps Kennicot. 



No yellow ring at base of head. Texas, New Mexico. 



TantUla gracilis Baird and Girard. 



Coloration like preceding species, but six supralabial plates instead of seven. 



Missouri to Texas. 



Genus MANOLEPIS Cope. 



Manolepis Cope, Proc. Amer. Phil. Soc, 1885, 76. — Boulenger, Cat. Brit. Mus. Ill, 1896, 120. 



Maxillary teeth equal anteriorly to grooved teeth, which are enlarged; anterior 

 mandibular teeth longer than posterior. Head distinct from neck. Pupil vertical. 

 Scales smooth, pitless. Anal and subcaudal undivided. There are discrepancies 

 in the descriptions of different authors. 



Manolepis putnamii l Jan. 



Anterior maxillary and mandibular teeth longer than median. Pupil round. 

 Body cylindrical, stout; neck but little constricted; muzzle protruded beyond labial 

 margin, oblique, truncate in profile; head acuminate and oval. 



Genus COKOPHIS Peters. 



An elongated, grooved tooth separated from others by an interspace. This 

 genus is rather an isolated American variety, and it is quite similar to and probably 

 allied to the African genus Rhamphiophis Peters. Both genera have decurved 

 muzzle and claw-like rostral plate, designed for scooping a cavity in the soil by a 

 downward movement. Three species are recorded, all Mexican. 



Genus CONIOPHANES HaUowell. 



Erythrolamprus Cope, Bull. U. S. Nat. Mus., 1887, 55. — Boulenger, Cat. Brit. Mus., Snakes, III, 

 1895, 199. 



Posterior maxillary teeth elongate and grooved. Pupil round. Loreal present. 

 Scales smooth and pitless. Anal and subcaudal divided. Typical species are 

 brown or red, with black stripes and delicate and handsome tints. Nine species 

 described, with one exception confined to Central America and Mexico. 



Coniophanes imperialis Baird. 



Erythrolamprus imperialis Boulenger, Cat. Brit. Mus., Snakes, III, 1896, 206. 



Scales in nineteen rows. Sides dark; a median dorsal band of varying width; 

 ventral red. According to the number of labials it is divided into two subspecies. 



1 In many respects this may be an Aglyphodont colubrine belonging to Dromicus putnamii Cope. 



