THE COMMON ENGLISH SNAKE. 327 



to a second genus,* is very repulsive in its aspect ; and its swollen, lips, covered by large hidden fangs, 

 give it the appearance of a venomous Snake. It has a wide geographical range in the Himalayas, 

 and the mainland to China, and in. the great islands. 



THE RACHIODONT FAMILY. 



An egg-swallowing Snake is found in South Africa, t and there are several other species of its 

 genus which probably swallow eggs, and have a peculiar structural arrangement in relation to this 

 food. Dr. Smith writes : " The paucity and smallness of the teeth in the mouth are favourable to 

 the passage of the egg, and permit it to progress without injury ; whereas, were they otherwise, many 

 eggs which have thin shells would be broken before they entered the gullet, and the animal, in 

 consequence, would be deprived of its natural food when within, its reach. Having observed 

 that living specimens which I kept in confinement always retained the egg stationary about two 

 inches behind the head, and while in that position made great efforts to crush it, I killed one, and 

 found the gular teeth about the place where the egg ceases to descend." Those teeth assist in fixing 

 the egg, and also in breaking the shell as the muscles contract around the throat. The instant the 

 egg is broken the shell is ejected from the mouth, and the fluid contents are carried down to the 

 stomach. The so-callecl gular teeth are really the tips of the long inferior spines of eight or nine of the 

 first vertebrae. Their tips are covered with an enamel-like substance which projects through the 

 coats of the gullet, or oesophagus, into its cavity. This is one of the most striking instances of a 

 " final cause " in nature, and the case stands isolated. 



There is a family of Fresh- water Snakes J which, Gunther notices, may be recognised by the posi- 

 tion of the nostrils on the top of the snout, which enables them to breathe by raising but a very small part 

 of the head out of the water. It is the same arrangement as that seen in the Sea Snakes. There are 

 several genera, and the species are usually small in size. They range widely in British India and the 

 islands of the mainland of Asia. The species Uipistes hydrinus greatly resembles a true Hydrophis 

 (p. 310). It lives in the sea, but it is not a venomous kind. The Long-nosed Herpeton, a Fresh- 

 water Snake, is remarkable for having two flexible " feelers," which are as long as its snout. They 

 are probably of use when the Snake is under water. It is found only in the southern parts of Siam. 



FAMILY COLUBRID^E. THE COLUBRIDES. 



This is a very large family, and the following is a general description of the Snakes which form 

 its numerous sub-families and genera : The head is distinct from the neck, not very large, and plated. 

 The teeth are numerous, and those of the upper jaw diminish in size from before backwards. The tail 

 has a double row of scales beneath, and there are no vestiges of limbs, nor is the body rigid as in the 

 next family. This important family is subdivided, and contains several sub-families, of which the 

 Smooth Snakes of Europe, the Common English Snake, and ^sculapius Snake, are types, and they 

 are the Coronellinse, Natricinse, Colubrinse, and Dryadinse. The family is very widely diffused. 



SUB-FAMILY NATRICIN.E. 



There is a common Snake, which frequents many parts of England, and especially places where 

 water is readily reached. By no means uncommon, they are nevertheless rarely seen except by those 

 people who look for them, and, indeed, many of the unobservant live in counties where the Snake 

 is excessively common, and yet never see a specimen. As this Snake is very fond of the water, 

 and swims with ease, and frequents ponds where there are frogs to be caught, it is often called 

 the Water-Snake. It is a slender reptile, with the back part of the head broader than the neck, and 

 the head is rather flattened and ovate in shape. The plates are broad and flat, and there are seven 

 labials. The body is very long, and the middle line of the back is elevated ; the tail is tapering and 

 about one-fifth of the entire length. The scales of the back are oval, imbricated, and each has a keel ; 

 those of the sides are broader and less keeled. The abdominal plates are broad, and number 

 170, whilst the sub-caudals are in pairs from sixty to sixty-five in number. The upper parts of the 

 body and head are of a light brownish-grey with a green, tinge, sometimes approaching to a dull pale 

 olive. Behind the head, on the upper part, is a broad collar, or two curved spots of a bright yellow 



* Psammodynastes. t Dasypcltis scdber. J Homalopsidce, 



Tropidonotus natrix (Kuhl) ; or, Natrix torquata (Ray). 



