10. 
al. 
14. 
15. 
SNAKES. 83 
. Liasts. Upper and lower labial shields pitted; muzzle and 
space between the eyes shielded. 
- Narpoa. Lower labial shields pitted ; crown with eleven sym- 
metrical shields. 
. Subcaudal plates entire, one-rowed ; intermaxillary or incisive 
teeth none ; superorbital line none. 
a. Scales smooth ; labial shields pitted. 
. Eptcrates. Forehead with symmetrical shields ; crown scaly. 
America. 
. XrpHosoma. Forehead and crown scaly; muzzle with regular 
shields ; labial plates short and all pitted. America. 
. Coratius. Forehead and crown scaly; muzzle with regular 
shields ; labial shields short, hinder ones pitted. America. 
. Sanzinta. Forehead and crown scaly; muzzle with regular 
shields ; labial shields elongate, prismatic. Madagascar. 
Curtis, Forehead and crown scaly; muzzle with regular 
shields ; labial shields broad, low. Asia. 
b. Scales smooth ; labial shields smooth, not pitted. 
Boa. Crown covered with scales ; nostrils lateral, between two 
plates. America. 
. PeLtopuitus. Crown covered with irregular plates ; nostrils 
lateral, between two scales. America. 
. Eunectes. Crown covered with irregular shields; nostrils 
vertical, between three plates. America. 
CuitasotHurus. Crown covered with regular shields ; nostrils 
lateral, between three scales. Madagascar. 
c. Scales keeled ; labial shields not pitted ; nostrils between 
two plates. America. 
Uneatra. Head covered with symmetrical shields. 
