The Zoologist— May, 1869. 1661 



in the same specimens were 28, 28, 29, 33 and 34 pairs. In Parting- 

 ton's 'British Cyclopedia' (1837) the ventral plates are said to vary in 

 number from 144 to 177, and the caudal plates from 29 to 68. Pro- 

 fessor Bell (1849), Lord Clermont (1859), and Mr. Cooke ('Our 

 British Reptiles,' 1865), agree in staling the number of ventral scutes 

 to be " about 140 to 150, and the subcaudal scutes about thirty-five 

 pairs." 



The ground colour is very variable : I have killed vipers in which 

 it was pulty-coloured, ochreous-yellow, brick-dust-red, umber-brown, 

 and dull black. Probably this variation in ground colour is due in a 

 degree to the age of the skin, or, in other words, to the greater or less 

 length of time that has elapsed since the last ecrlysis or moult — a 

 contingency not sufficiently appreciated by naturalists who, having a 

 dead viper of somewhat abnormal colouring brought to them, at once 

 proceed to describe it as a variety or even as a species. Those who 

 have observed a viper in captivity, particularly before and after an 

 ecdysis, must have been struck with the altered tint and greater 

 brilliancy of markings immediately after the completion of that event. 

 But whatever the ground colour, there is almost invariably a dark 

 brown, niedio-dorsal, sinuous stripe commencing behind the head, and 

 nearly reaching the tail, where it becomes broken up into spots or 

 blotches. Sometimes this stripe is interrupted throughout its course, 

 and iis place occupied by a series of trapeziform blotches connected 

 together by a mere thread of the same dark colour ; and sometimes 

 again, although very rarely, this connecting thread is wanting and the 

 stripe is replaced by a series of black spots or blotches : on each side 

 of the body there is also a row of nearly circular black spots, and on 

 the crown of the head is a single black blotch, always separate from 

 the medio-dorsal stripe and divided posteriorly in the form of a letter 

 V, so as to include the anterior extremity of the said stripe : the 

 scutes covering the margin of the upper jaw are whitish and generally 

 four in number; those on the margin of the lower jaw are yellowish, 

 smaller and seven or eight in number. 



The average length of a viper is two feet; the females are longer 

 than the males, and when pregnant very ranch stouter: I have rarely- 

 seen a viper much exceeding the length I have mentioned, and those 

 which are shorter are generally young and immature 



The viper produces its young alive, and although there is an invest- 

 ing, flexible pellicle to each, somewhat analogous to that found in the 

 egg of the domestic fowl within the calcareous shell, yet this is 



