.OO REPTILES. 



former are subdivided into the venomous with several maxillary teeth, and 

 the venomous with insulated fangs. 



In the non-venomous, the branches of the upper jaw as well as those 

 of the lower one, and the palatine arches, are every where furnished with 

 fixed and solid teeth ; there are then four equal rows of these teeth in the 

 upper part of the mouth, and two below *. 



Those of the non- venomous, which have the mastoid processes com- 

 prised in the cranium, the orbit incomplete behind, and a thick, short 

 tongue, still retain much similitude to the Double-walkers, AtnjMshcencP, 

 in the cylindrical form of their head and body; they were formerly united 

 with the Anguis, on account of their small scales. They constitute the 

 Rollers. 



ToRTRixf, Oppel. 



They are otherwise distinguished from the Anguina, even externally, 

 inasmuch as the scales which form the range along the belly and under 

 part of the tail are a little larger than the others, and the tail itseK is ex- 

 tremely short. They have but one lung. 



The species known are from America, the most common must be 

 Jncjuis scytale, L., Seb. II, xx, 3. (The Ribbon). Two feet long, 

 irregularly annulated, white and black \. The 



Uropeltis, Cuv., 



Is a new genus allied to Tortrix, in which the tail is still shorter, and 

 obliquely truncated above, the truncated surface flat, and studded with 

 granules. The head is very small, the muzzle pointed; there is a range 

 of scales along the belly somewhat larger than the others, and a double 

 range of them under their stump of a tail§. 



In those non-venomous Serpents, on the contrary, in which the mastoid 

 bones are detached, and the jaws are susceptible of great dilatation, the 

 occiput is more or less enlarged, and the tongue forked and very ex- 

 tensible. 



* The common opinion respecting them is, tliat those which are destitute of the 

 pierced fangs in front of the jaws are not venomous, but I have some reason to doubt 

 its correctness. They all have a maxillarj^ gland, which is frequently very large, and 

 their back molars exhibit a groove which may serve to convey some fluid. It is very 

 certain that several of the species in which the back molars are very large, are ac- 

 counted extremely venomous in the countries they inhabit, and that the experiments 

 of Lalande and Leschenault have served to confirm that opinion; the repetition of 

 these experiments is much to be desired. 



t They are the Anilius, Oken, the Torquatrix, Gray, and the Ilysia, Hemp- 

 rich and Fitzinger. 



:J: Add, Ang. coraUinus, Seb. II, Ixxiii, 2, 1, 3, which is perhaps a mere variety of 

 the scytale; — Ang. ater, Id. XXV, 1, and VII, 3; — Tortr. rtifa, Merr., which seems 

 to me a variety of the atra; — Aug. maculaius and tcssellaius, Seb. II, c. 2; — F. latta, 

 N. Seba, II, xxx, 3; Russel, XhW ;— Tort, punctata, Nob., Seb. II, 11, 1, 2, 3, 4, 

 and VI, 1, 4. 



§ Uropeltis ceylan'icus, Nob. ; Urop. phillppinus ; two new species, similar to the 

 Tortrices even in colour. 



