CLASS REPTILIA 539 



Ventral scales transversely enlarged; eyes functional 

 and free. 

 Subfamily i. PYTHONIN.E. PYTHONS. Examples: Lox- 



ocemus, Liasis, Python (Fig. 460). 

 Subfamily 2 . BOIN.E. BOAS. Examples : Epicrates, 



Boa, Ungalia. 



Family 4. COLUBRID.E. - - HARMLESS and POISONOUS 

 SNAKES. SERPENTES with facial bones movable; both 

 jaws toothed. 

 Series A. AGLYPHA. -- COLUBRHXE with solid teeth, not grooved 



or tubular. Non-venomous. 



Subfamily i. COLUBRIN.E. - TYPICAL HARMLESS 

 SNAKES. - Examples: Thamnophis (Fig. 461), Zamc- 

 nis, Elaphe. 

 Series B. OPISTHOGLYPHA. COLUBRID.E with grooved fangs in 



the rear of the upper jaw. Venomous. 

 Subfamily 2. HOMALOPSIN.E. -- RIVER SNAKES. Ex- 

 amples: Hypsirhina, Homalopsis. 

 Subfamily 3. DIPSADOMORPHIN.-E. Examples: Taniilla, 



Philodryas, Oxyrhopus. 

 Series C. PROTEROGLYPHA. - - COLUBRID.E w T ith fangs in the 



front of the upper jaw. Venomous. 

 Subfamily 4. HYDRIN.E. - - SEA-SNAKES. - - Examples : 



Hydrophis, Distira, Platurus. 

 Subfamily 5. ELAPIN^E. COBRAS and CORAL-SNAKES. 



Examples: Naja (Fig. 462), Elaps, Denisonia. 

 Family 5. VIPERID.E. - -THICK-BODIED POISONOUS SNAKES. 

 - Poisonous SERPENTES with a pair of large perforated 

 fangs. 

 Subfamily i. VIPERIN^:. - - TRUE VIPERS. Examples: 



Viper a, Atractaspis. 



Subfamily 2. CROTALIN^:. - - PIT- VIPERS. - - Examples: 

 Crotalus (Fig. 466), Agkistrodon (Figs. 463 and 464),, 

 Lachesis. 



