2. No vestiges of limbs ; supratemporal absent. 



5. Uropeltidae, Vol. I. p. 137. 



B. Coronoid absent ; supratemporal present. 



1. Maxillary horizontal ; pterygoid reaching quadrate or 

 mandible. 



Praefrontal bone in contact with nasal. 



6. Xenopeltidae, Vol. I, p. 167. 



Prsefrontal not in contact with nasal. 



• 7. Colubridae, Vol. I. p. 169. 



2. MaxiUary horizontal, converging posteriorly towards 

 palatine ; pterygoid not reaching quadrate or mandible. 



8. Amblycephalidae. 



3. Maxillary vertically erectile perpendicularly to ecto- 

 pterygoid ; pterygoid reaching quadrate or mandible. 



• 9. Viperidse. 



No serial arrangement can convey a correct idea of the affinities 

 of the various groups as couceived by the classificator. A diagram 

 is therefore appended illustrating the author's views on the classifi- 

 cation of the Ophidia, and, to a certain extent, their phylogeny. 

 Leaving aside the Typhlopes and Glaucoma', which should be 

 regarded as degraded burrowing types independently derived from 

 some Ophidian form less specialized than any with which we are at 

 present acquainted, the family iJoiVZoK, and more specially the Pythons, 

 claim the position of ancestral group from which all other Ophidia 

 may have been derived, in the manner illustrated by the diagram. 

 This, if rightly conceived, shows how unnatural a classification 

 into poisonous and harmless Snakes is. The Elapoids, for instance, 

 long regarded as forming the passage from the Colubroids to the 

 Vipers, stand apart, the author considering the Viperine maxillary 

 as derived from the Opisthoglyphous type. 



9. Viperidce. 



8. Aniblycephalidce . 

 5. Uropeltidce. 7 a. C. OpisthoglijiAa. 7 b. C. Vrotero(jlypha. 



U- 



4. Ilysiide. 6. Xenopeltida. 7. Coluhridcs {Aglypha). 

 I 1 I 



1. TyphlopidcB. 3. Boidm. 2. Glauconiidce. 



