REPTILES 211 



Ci Head not distinct from neck; no pit between eye and 



nostril 4. Elapidce. 



Co Head very distinct; a pit between eye and nostril 



(Fig. 127) 5. CrotalidcB. 



Family i. Leptotyphlopidae. — Small, blind, worm-like snakes 

 with rudiments (not visible) of hind legs and a pelvic girdle : 2 general 

 and species in America. 



1. Leptotyphlops Fitzinger. Supraocular plates present: several 

 species; i in the United States. 



L. diilcis (Baird & Girard). Length 200 mm.; tail 10 mm.; color 

 pale brown above; white beneath; scales in 14 rows: Texas and New 

 Mexico; burrowing in soft soil, often in ant-hills. 



2. Siagonodon Peters. Supraocular plates absent: i species. 

 S. humilis (Baird & Girard). Body hke preceding: Arizona and 



southern California. 



Family 2. Boidae. — The Boas. Mostly large, arboreal constrictor 

 snakes in which rudiments of hind legs and a pelvic girdle are present 

 in form of a pair of spurs near the anus; scales smooth: many species, 

 cosmopolitan; 2 species in the United States, both small. The family 

 includes the boa-constrictors of South America and the pythons of 

 Africa, Asia and the East Indias, which are the largest snakes, reach- 

 ing a length of 35 feet. 



1. Lichanura Cope. Form stout; tail obtuse; head covered with 

 scales: several species. 



L. roseofusca Cope. Length 788 mm.; tail 115 mm.; rows of scales 

 33 to 42; ventrals 229; subcaudals 49; color bluish gray or brown; 

 abdomen red: southern California and Arizona. 



2. Charina Gray. Small snakes with very small scales; head 

 covered with plates : 2 species. 



C. hottcB (Blainville). Rubber snake; ball snake. Length 600 

 mm. ; tail 70 mm. ; color brown or gray, yellow beneath; tail very blunt; 

 rows or scales 42 to 47; upper labials 9 to 11; ventrals 200: Nevada 

 and CaUfornia to Idaho and Washington; common in humid regions, 

 feeding on mice, etc. 



Family 3. Colubridae. — Snakes with many conical teeth in both 

 jaws; without poison fangs in the front part of the mouth (but certain 

 genera, the opisthoglyph snakes,^ are poisonous, one or more pairs 

 of teeth at the rear of the upper jaw being elongate and grooved and 

 forming the poison fangs, such snakes in the United States, however, 



^The opisthoglyph genera in the United States are the following: 5o«ora, Hypsiglena, 

 Tantilla, Trimorphodou. 



