12 AUSTRALIAN SNAKES. 



It is the pleated condition of the scales which 

 enables the snake to cast its outer skin, a process known 

 as sloughing. If each scale was a separate structure 

 this would not be possible, and in a slough the 

 scales do not overlap, due to the straightening out of 

 the skin ; the length of a slough is therefore greater 

 than that of the snake from which it was cast, and 

 presents the appearance of a thin membrane studded 

 with regular, but slightly separated, scales. On the 

 head the scaling usually takes the form of large 

 symmetrical plates, which are, however, not imbricate, 

 but arranged side by side so tliat in a cast skin they 

 present exactly the appearance they did when on the 

 snake. It is, therefore, in many cases, possible to 

 determine the species from the slough alone. In a 

 healthy snake the skin is usually cast whole ; the head 

 is first freed and the slough is drawn inside out as 

 the snake disrobes ; the tail is, however, frequently 

 slipped out, in which case the slough of that member 

 retains its original aspect. 



The slough includes a thin, transparent covering 

 from the eye, this retains its position in the cast skin and 

 the only openings in the slough are those naturally of 

 the body. It has been stated that as the new skin 

 forms beneath the old one, the eye becomes dull and 

 opaque, and the snake is blind for a few days at this 

 time. Having several times watched this process of 

 sloughing, it did not seem to me that the subject was 



