CHAPTER VII. 



THE BRITISH REPTILES, 



HTHERE are but nine British reptiles, and with the exception of 

 ^ the three lizards, these all belong to different genera. The 

 seven genera represent six different families belonging to five 

 orders and two of the sub-classes. These sub-classes are Chelonia 

 (turtles and tortoises), and Sauria (lizards and snakes), and of 

 each two orders of the first, Atheca and Thecophora, there is 

 one example, while both the Saurian orders, Lacertilia and 

 Ophidia are represented by two families. 



The Chelonians are distinctive enough to be summarily dealt 

 with. The Leathery Turtle (Sphargis, 74) has the shell covered with 

 leathery skin without epidermal shields ; the Hawksbill (Chelone, 73) 

 has the shell covered with horny shields. Needless to say, both 

 these turtles have become British by misadventure. 



The snakes and lizards, which are all genuine Britons, with one 

 doubtful exception, require more careful treatment. There are two 

 orders of Sauria : 



1. Lacertilia, in which the right and left halves of the lower jaw 



are united by a bony suture. 



2. Ophidia, in which the bony suture is replaced by an elastic 



ligament. 



This seems but a feeble and ultra-technical way of separating the 

 lizards from the snakes, but it is really the only essential difference. 

 The presence or absence of legs is no guide, as among the ophidians 

 are the pythons, boas, and cylinder snakes, which have external 

 vestiges of hind limbs, and among the lizards are some which have 

 no visible legs, as, for instance, the Slow-worm (Anguis) which is the 

 first lizard on the British list, and is thereby distinguishable from 

 the other three, all of which have legs. Our first table is con 

 sequently simple. 



LACEKTILIA 



1. (Anguidae) 



No visible legs. Anguis, 75. 



2. (Lacertidae) 



JLegs well developed. Lacerta, 76 to 78, 



