REPTILES. 



297 



parative length of the bodies, and in the gradual diminu- 

 tion and ultimate disappearance of the extremities. In 

 the genus Scincus, for instance, the limbs are already less 

 robust than those of the true Saurians ; the two pairs are 

 also more distant from each other, in consequence of the 

 greater comparative elongation of the body. There are as 

 yet five perfect toes on each foot, which, however, are 

 shorter and more even in their relative proportions than 

 in the true Saurians. These deviations become increased 

 m the genus Ckalcides, and still more in Seps, which has a 

 very elongated body, the limbs extremely small, and the 

 toes only four or three on each foot. In Monodadylus a 

 further reduction takes place in the development of the 

 limbs, which have dwindled to a mere little undivided 

 finger; they are still, however, four in number; but in the 

 genus Bipes the anterior ones have wholly disappeared, and 

 are found in a rudimentary state under the integument, 

 the posterior ones constituting only small undivided pro- 

 cesses. These also being removed, the Ophidian form of 

 the present genus, and those of Tortrix, Typhlops, and others, 

 with all the Amphisbcenadce, succeed, in which the bones of 

 the shoulder, the sternum, and the pelvis, exist in a more 

 or less rudimentary condition, and lead us toward the true 

 Snakes, in which all these parts are lost, excepting the 

 rudiment of a posterior extremity, which in the Boa appears 

 externally in the form of a small horny hook, or holder, 

 on each side of the vent." * 



Besides the Slow-worm, w T e have in the British Isles but 

 two representatives of the vast Lizard group — the Order 

 Sauria. One of these is the elegant Sand Lizard of our 



• "British Reptiles," ». 40, 



