THE OPHIDIA. 27 



slender, harmless snakes very long tails, tapering so gradually lhat 

 you cannot readily decide where the tail begins. But there are 

 exceptions. When a snake is about to cast its cuticle you will 

 see it pushing its jaws against the gravel in the cage or whatever 

 rough surface may be there, and turning its head over to rub first 

 one side and then the other and the top. Presently the skin is 

 loosened round the lips, and by continual rubbing and being 

 pushed folds back, the upper part over the head and the lower 

 over the throat ; and when the head is free no more rubbing is 

 necessary, as the snake has only to crawl, and keep on crawling 

 as it emerges bright and beautiful from the slough. It is as if 

 some one were pulling off your tight coat sleeve beginning at the 

 shoulder, the sleeve turning inside-out as it is drawn down to the 

 wrist, only the person holding your sleeve remains still, while you 

 (like the snake) move away and leave it. The shoulder represents 

 the head of the snake and the wrist the tail. The last few 

 inches of tail generally slip out unreversed. If a snake is in 

 good health and sheds well, the whole process does not occupy 

 many minutes, but if the skin is in an unhealthy condition the 

 snake has more difficulty, or makes no effort, and the cuticle 

 comes off in pieces. A very curious and interesting object is 

 the cast-off coat, showing the imbricated arrangement of the 

 *' scales," so called because externally they have this appearance 

 from the folds in the skin, though unlike the scales of some 

 fishes which come off separately, the snake skin is entire. The 

 eye covering is round and clear, like a miniature watch glass ; 

 snakes not having eyelids can never close their eyes, which are 

 protected by this transparent covering. It is cast with ' the 

 cuticle ; and if you examine the slough of a snake you will 

 observe that the transparent eye scale is of a stronger texture than 

 the rest, and set in a framework of small scales ; while on the 

 reverse side it stands out distinct from them in a cup-like form, as 

 here represented (fig. 9). This little drawing, taken from nature, 

 is a trifle exaggerated in order to show the form 

 distinctly. The period of sloughing is irregular, some- 

 times once but more frequently four or five times a 

 year. Snakes are fastidious creatures, and whenever Flg ' 9 " 

 their coat is soiled or uncomfortable they doff it and come out 

 resplendent in a new one, which displays its colours to perfection. 

 The snake, too, feels invigorated, and is ready for dinner, having 

 been somewhat an invalid for several days previously, and hidden 

 in some corner declining food. Young snakes invariably cast their 

 cuticle at a very early day, and very frequently while growing. 

 It only remains to say that the form and position of the head 



