4 COHTBEIB^. 



tttt Internasals fused witli the prsefrontals, nasai 

 fused with, the first labial. 



87. SymphoUs, II. p. 188. 



/3. Posterior maxiUary teeth strongly enlarged and sepa- 

 rated from the rest by a very distinct interspace. 



* Scales with apical pits ; snout rounded or obtusely 

 conical. 



Scales forming longitudinal series ; no suboculars. y' 



75. Liophis, II. p. 126. 



Scales forming longitudinal series ; a series of suboculars. 



76. Cyclagras, II. p. 144. ^' 



Scales disposed obliquely ; no suboculars. 



77. Xenodon, II. p. 144. X 



** Scales with apical pits; snout projecting, cunei- 

 form. 



Scales smooth, in 19 or 21 rows. 



78. LystropMs, II. p. 151. ^ 



Scales keeled, in 23 to 27 rows. 79. Heterodon, II. p. 153. 



*** Scales without pits ; snout obtuse ; head narrow. 

 80. Aporophis, II. p. 157. >\ 



e. Longitudinal series of scales in odd numbers ; ventrals 

 with a suture-like lateral keel, and a notch on each 

 side corresponding to the keel. 



a. Scales of vertebral row not enlarged. 



Scales smooth ; subcaudals keeled and notched like the ventrals. 



67. PhUothamnus, II. p. 98. 



Scales keeled ; subcaudals keeled and notched like the ventrals. 



68. Gastropyxis, II. p. 102. 



Scales keeled ; subcaudals without keel or notch. 



69. Hapsidophrys, II. p. 103. 



0. Scales of vertebral row enlarged. 



64. DendropHs, II. p. 77. 



4. Palatine and pterygoid teeth absent or few ; maxillary bone 

 short, with 5 to 8 teeth. 



a. MaxiUary teeth forming an uninterrupted series. 

 PupU round; snout projecting, obtuse. 



93. Oligodon, II. P.-233. 



Pupil vertically subelliptic ; snout with angular horizontal edge. 



94. Prosymna, II. p. 246, 



