THE PBIMAKY ORDERS OF THE CLASS. 107 



where all those gigantic herbivorous monsters of former 

 stages come in, as part and parcel of one of the most 

 natural groups in Zoology, which ^roup, without these, 

 would exhibit nothing but broken or isolated links of 

 what we have shown to be a continuous chain. Equally 

 remarkable are those extinct reptiles which belong to 

 the class of animals now before us ; and it is therefore 

 obvious, that if those which have hitherto been dis- 

 covered should be here omitted, our arrangement would 

 be altogether partial : it might, indeed, be made to 

 appear very plausible on paper, but no philosophic 

 naturalist would attach to it either credit or authority. 

 True it is that in the arrangement which we shall now 

 submit to such inquirers, several intervals or inter- 

 ruptions in the otherwise gradual chain of continuity 

 will be found ; but these, comparatively, will be few, 

 while, from the zeal and ability with which the study 

 of Fossil Zoology is now prosecuted, every fresh dis- 

 covery will diminish the number of these gaps, by 

 bringing to light some intermediate form necessary to 

 connect others which are now in existence. Upon 

 these principles we are now to ascertain the probable 

 course of the natural groups in the class before us. 



(112.) The primary orders of the reptiles appear to be 

 these, and they wOl be characterised in as simple terms as 

 possible. The first is composed of the serpents or 

 Ophides, having the body destitute of any feet, and 

 covered with scales. These crawl upon their belly, 

 and, although a few of them are aquatic, the greater 

 portion live upon dry land. Towards the termination 

 of the series, we begin to find the rudiments of feet, as 

 in the slow worms, first internally, then externally, 

 and finally little appendages, as it were, which are 

 cleft at their tips into minute toes. These conduct us, 

 by a most beautiful series of gradations, to the second 

 great division — the Saures, or lizards, whose body is 

 not only covered with scales like that of the serpents, 

 but is likewise furnished with four distinct feet : they 

 are all terrestrial, and consequently have their toes 



