the same size? They generally are, but some snakes have 

 the vertebral row enlarged (Fig. 7), notably the krait ; and, 

 secondly, notice whether the scales are smooth or whether 

 there is a raised keel along the centre of each scaJie. 



We may also notice whether the scales merely touch 

 one another or whether they more or less overlap, when they 

 are said to be imbricate. 



Now a few words about the shape or form of snakes 

 generally. 



The head may be narrow and elongated or broad and 

 stumpy, Moreover it may be quite distinct from the rest of 

 the body, being separated by a sort of neck ; or there may 

 be no neck so that the head is not distinct. 



Some snakes have elongated, slender bodies, others stout 

 heavy ones. 



And in some the tail is short and stumpy, in others very 

 long, or tapering away into a fine, minute point. 



The size of the eye varies too. Some snakes have large 

 eyes, others small and others again moderately sized ones, 

 The coloured part of the eye or iris varies ; in some it is 

 black, in others green or golden. When it is black the 

 shape of the pupil cannot be made out but the pupil also 

 varies ; in some being round, in ' others a vertical or hori- 

 zontal slit. 



The nostrils are generally on the side of the face, but in 

 the water and sea snakes they are on the crowu of the head 

 and are then said to be " superior." 



Let us now study the teeth of snakes. 



We will deal first with the teeth of harmless snakes. 



There are altogether six rows of teeth — two rows in the 

 lower jaw and four in the upper. These consist of a row of 

 teeth on each side of the mouth in both the upper and lower 

 jaws. These four rows may be called, for convenience, the 

 upper and lower marginal rows. In addition to these, in 



