Royal Physical Society. 181 



be taken in the hand and allowed to urge itself through the 

 fingers, placed in such a way as to keep back the scales, de- 

 tachment is effected in a few minutes — the animal, in apparent 

 ecstacy, working its way out of its skin with elevated head 

 and with lightning-like rapidity, playing, in its characteristic 

 way, its long nimble tongue. But there are states, either of 

 the animal itself, or arising from its treatment, when slough- 

 ing seems difficult ; the scales seem too dry, are comparatively 

 inflexible, and remain about the body in rings and shreds till 

 bit by bit they are detached. 



4. The Slough. — The slough, as thrown off from the body, 

 is a mass of scales — not huddled or inverted, but regularly 

 laid one upon another, and compacted into a very small space — 

 an inch or two of the tail portion generally remaining free. 

 When newly detached, the slough may be drawn out to fully 

 one and a half the length of the animal. The scales of the 

 head, which are smooth and very varied in size, are so ar- 

 ranged on the upper jaw as to admit of no extension, while 

 those of the under jaw, with the exception of two rows of 

 small scales which cover the bone, are like the other body 

 scales. The largest scales of the animal are the central ones 

 of the head and those within the angle of the lower jaw, and 

 the smallest are those of the labia and of the eyelids. The 

 scales of the body, individually, are also smooth, somewhat 

 rhomboid, and collectively are arranged in an imbricated man- 

 ner, each being encroached upon, and encroaching, to the ex- 

 tent of one-third, and each having connection with three above 

 and three below. The point of connection of one scale with an- 

 other is the upper border, and each reposes on its scale-plate, 

 the edge of the scale extending beyond the plate ; and the 

 whole is united by highly elastic tissue, — an arrangement 

 which admits of great expansion and flexibility. 



The usual method of enumerating the scales of snakes is 

 scarcely applicable to this species of reptile, for the scales of 

 the entire body, unlike most serpents, are of uniform charac- 

 ter. Counting from the margin of the upper jaw along the 

 back, there were, in a specimen carefully examined, 273 rows 

 of scales in the whole length of the animal — 7 in the head, 



