Three plates on the upper part of the head, larger than the surrounding scales; dorsal scales carinated: a series of confluent rhomboidal black spots down the back.
V. communis, Leach, Zool. Misc. vol. iii. p. 7. Flem. Brit. An. p. 156. Vipera, Ray, Syn. Quad. p. 285. Coluber Berus, Turt. Brit. Faun. p. 80. Viper, Penn. Brit. Zool. vol. iii. p. 26. pl. 4. no. 12. Common Viper, Shaw, Gen. Zool. vol. 111. p. 365. pl. 101.
Length from one and a half to two feet; rarely more.
(Form). Shorter, and, in proportion to its length, thicker, than the Natrix torquata. Head depressed, widening behind the eyes; neck somewhat contracted; gape as long as the head, slightly ascending posteriorly; jaws very dilatable; two rows of fine teeth on the palatines, but none on the maxillaries, besides the poison-fangs: body gradually increasing in thickness to about the middle of the entire length, from that point scarcely diminishing to the vent, beyond which it tapers quite suddenly: tail very short, not one-ninth of the entire length, terminating in a sharp point: upper part of the head covered with small squamous plates, different from the imbricated scales of the back; of these plates three are larger than the rest, one situate in the middle between the eyes, the two others immediately behind the first: dorsal scales imbricated, oval approaching triangular, carinated; increasing in size towards the sides of the body, where the longitudinal keel becomes lost: beneath the lower jaw some imbricated scales without a keel: plates of the belly transverse, oblong, about one hundred and forty-three in number; sub-caudal plates about thirty-three on each side. (Colours). Extremely variable: ground of the back and upper parts, in some, dirty yellow; in others olive, or pale cinereous brown: space between the eyes, and an oval patch on each side of the occiput, black or dark brown; a zigzag dorsal fascia of the same colour commencing at the nape and reaching to the extremity of the tail (in some the fascia assumes rather the appearance of a longitudinal row of confluent diamond-shaped spots); also a row of small triangular black spots along each side parallel to the dorsal fascia: belly, and beneath the tail, steel-blue, stained in some places with yellowish; sometimes almost wholly black. Obs. The markings above vary much in intensity of colouring, but always preserve, those on the head especially, nearly the same form. The following are some of the principal varieties noticed by authors.
Var.β . Red Viper. Rackett in Linn. Trans, vol. xn. p. 349. Strickland in Loud. Mag. of Nat. Hist. vol. vi. p. 399. Gray in Proceed, of Zool. Soc. (1834) p. 101. Coluber Chersea, Linn. Syst. Nat. torn. i. p. 377. Petite Vipere, Cuv. Reg. An. torn. ii. p. 92. " Of a bright ferruginous red, with zigzag markings down the back, resembling in form those of the Common Viper; but instead of being black or dark brown, they are of a deep mahogany colour: also a series of irregular spots of the same colour along each side: the zigzag line terminates at the back of the head in a heart-shaped spot, placed between two converging dark-coloured bands, which meet on the top of the head, and again diverge towards the eyes: belly ferruginous, like the back. Head much broader and shorter than in the Common Viper." Strickl.
Var. y. Blue-bellied Viper. (Coluber caeruleus,) Shepp. in Linn. Trans, vol. vii. p. 56.
Var. 8. Black Viper. Leach, Zool. Misc. vol. iii. pl. 124. Coluber Prester, Linn. Syst. Nat. torn. i. p. 377. Wholly black, or very dark brown; the markings hardly distinguishable.
Common in many parts of the kingdom, frequenting thickets, old chalkpits, and other waste places, more especially where the soil is dry. Said to be most abundant in the Western Islands. In Cambridgeshire very rare. Feeds on mice, frogs, and insects. Brings forth its young alive.
Var. β. was first obtained by the Rev. T. Rackett from Cranborne Chase, in Dorsetshire. It has been since met with in Suffolk, Worcestershire, Somersetshire, and Berkshire. By some it is considered as a distinct species; I have, however, no hesitation myself in regarding it as a mere variety of the common kind. The fact of its being always found of a small size is probably due to the circumstance of the colours changing in advanced life.
Var. y. was described by Mr Sheppard, who considered it as another distinct species. He does not state whence his specimen was obtained.
Var. δ. has been found in Suffolk, and a few other parts of England, but is very rare.
The Coluber Berus of Linnaeus is thought by Cuvier to be the same as his Vipere Commune, a species perfectly distinct from the Common Viper of England*.
* Obs. According to Mr. Lyell, (Prin. of Geol. vol. ii. p. 103). none of the above three species of Ophidian Reptiles have been observed hitherto in Ireland. According, however, to another author, (Edinb. New Phil. Journ. vol. xviii. p. 373). Snakes have been lately imported into that country, and, "arc at present (1835) multiplying rapidly within a few miles of the tomb of St. Patrick/'