156 REPTILES. OPHIDIA. Natrix. 



135. On the character derived from the number of scales either of the belly 

 or tail, no reliance can be placed ; so variable are they on individuals of the 

 same species. 



Gen. III. NATRIX. Snake. — Destitute of poison-fangs. 

 Four regular rows of imperforate teeth above, and two be- 

 low. 



3. N. torquata. Ringed Snake. — Head with nine large scales ; 

 dorsal scales oval, with a mesial ridge. 



Hydrus, Sibb. Scot. 28 Nat. torq. Ray, Syn. Quad. 334 — Coluber Na- 

 trix, Linn. Syst. i. 380. Perm. Brit. Zool. iii. 33— Collared Viper, 



Lac. Ov. Quad. iii. 34G E, Common Snake ; S, Water Snake ; W, 



Neidr fraith, Neidr y tome nydd.— Common in England ; rare in Scot- 

 land. 

 Length from 3 to 4 feet. Back dusky-brown, with two black stripes of 

 spots running the whole length, crossed by numerous irregular spots. Belly 

 dusky, with a bluish tinge; a spot of yellow, and another triangular one of 

 black on each side the neck. Head depressed ; muzzle rounded ; the large 

 scales in four rows, the first and second of two each ; the third of three, and 

 the fourth of two ; seventeen scales on each jaw. Scales of the sides small 

 and smooth. Belly variegated black, white, and bluish ; the plates of the belly 

 about 120 ; pairs of the tail 53, or even CO. Eggs 18 to 20, deposited in dung- 

 hills or hot-beds. Feeds on ants, frogs, and mice. Becomes torpid during 

 the winter. Easily tamed. Frequents marshy places, and enters the water 

 occasionally. 



4. N. Diimfrisiensis. Dumfries-shire Snake. — Dorsal scales 

 destitute of a mesial crest. 



Coluber Dum. Sower. Brit. Misc. tab. iii. 



" Plates on the belly, 1 62. Scales under the tail about 80. This coluber seems 

 to be entirely new, and was discovered by T. W. Simmons, near Dumfries. As 

 only one specimen has been seen, we cannot say much with regard to its usual 

 size. The figures are pretty accurately drawn, as to the size of the specimen 

 (about 5 inches). The scales of the back are extremely simple, not carinated. 

 It is of a pale colour, with pairs of reddish-brown stripes from side to side, 

 over the back, somewhat zigzag ; with intervening spots on the side." This 

 is all the information which has yet been acquired concerning this species. 

 There is no mention made of the large scales on the head, though they are 

 represented in the figure, and intimate that this cannot be the young of the 

 common viper ; while the smooth dorsal scales indicate that it is a distinct 

 species from the ringed snake. In the last character, it agrees with the smooth 

 viper, Col. Austriacus of Gmelin, a species common in Germany and France, 

 of which it may probably be only a variety. 



Gen. IV. VIPER A. Viper. — Maxillary bones with poison- 

 fansrs, btit no common teeth. Scales behind the vent di- 

 vided. Neck narrow. Head destitute of plates. 



5. V. communis Common Viper or Adder. — Dorsal scale s 

 oval, carinated ; inferior lateral ones suhangular and plain. 



