178 Proceedings of the 



in others, there are parallel lines or dots, giving the appear- 

 ance of three, five, and seven lines in different specimens, and 

 in many the centre line is entirely absent. Among eighteen 

 specimens examined at the time of writing, seven only pre- 

 sented the single central line down the back, which, never- 

 theless, is the prevailing form. In the young, on leaving the 

 egg, and for some time after, the colour of the back is generally 

 hazy yellow, with, in most instances, a straight black line down 

 the back, while the under three-fourths is glossy black. But 

 from the first there are distinct and numerous varieties of ex- 

 ternal markings. In an animal, under observation, three 

 years old, the characteristic centre line is wanting ; but the 

 yellowish-coloured part of the back is traversed by several 

 faint dark interrupted stripes, and on each side the scales of 

 the fore part of the body are beautifully marked with spots, 

 each of which consists of a dot of green and a dot of black. 

 In another, sixteen months old, also without the centre line, 

 interrupted dark spots pass down the body, and the scales of 

 the tail are each marked by sometimes two, and sometimes 

 three dark streaks, which give the tail a striped appearance. 

 In another specimen, two years old, there are not only three 

 black lines down the back, but between each, two others less 

 dark ; and these do not by any means comprise all the va- 

 rieties of external markings. 



But difference of age, or exceptional markings, do not suffi- 

 ciently compass the aspects of the animal, for the approach 

 of the sloughing periods, which are frequent, very materially 

 alters the appearance alike of the young and old. 



3. Dermal Covering and Sloughing. — The common notion 

 that a serpent " casts its old skin" once in the year does not 

 hold good as regards the slow-worm, though this is stated by 

 most popular writers. The dermal covering of this animal, 

 unlike that of serpents, but like some other reptiles and fishes, 

 is a beautifully arranged system of plates of bone, on which the 

 scales or cuticle repose. These, what I shall call scale-plates, 

 are permanent, and grow with the animal ; the scales, on the 

 contrary, are frequently renewed, particularly during the 

 growth of the animal. A specimen, in its eighth year, fed 

 regularly throughout the whole period while its own dormancy 



