DIPSADOMORPHIN &. 27 
Synopsis of the Genera. 
I. Hypapophyses present throughout the vertebral column, 
represented on the posterior dorsal vertebre by a more or 
less developed crest or tubercle projecting below the 
condyle. 
A. Solid maxillary teeth equal or subequal. 
1. Pupil round; body cylindrical ; scales smooth. 
Mandibular teeth subequal ; scales without pits. 
134. Geodipsas, p. 32. 
Anterior mandibular teeth strongly enlarged; scales without pits ; 
subcaudals single .......... 135. Hologerrhum, p. 33. 
Anterior mandibular teeth longest ; scales with apical pits. 
136, Ithycyphus, p. 34. 
2. Pupil vertical. 
a. Kye moderate ; body cylindrical. 
Snout ending in a long scaly appendage ; scales keeled. 
137. Langaha, p. 35. 
Snout without appendage; scales strongly keeled. 
138. Alluaudina, p. 38. 
Snout without appendage; scales smooth; a series of suboculars. 
139. Eteirodipsas, p. 38. 
b. Eye large; body compressed ; scales smooth. 
140. Stenophis, p. 39. 
B. Solid maxillary teeth very unequal; anterior mandibular 
teeth strongly enlarged; pupil vertical. 
Body compressed ; scales smooth ; tail long. 
141. Lycodryas, p. 44. 
Body cylindrical; scales smooth or obtusely keeled ; tail moderate, 
with single subcaudals ; nostril between nasal and supranasal, 
142, Pythonodipsas, p. 45. 
Body cylindrical; scales smooth ; tail short, with single subcaudals. 
143. Ditypophis, p. 46. 
II. Hypapophyses absent in the posterior dorsal vertebra. 
A. Solid maxillary teeth gradually decreasing in length, the 
anterior much longer than the posterior; head distinct 
from neck ; pupil vertical. 
1. Vertebral scales not enlarged. 
Body cylindrical or ae compressed; scales oblique; no sub- 
SOUIATS os. eat ads ce 144, Tarbophis, p. 47, 
