ORDO III. SAURIA. 



THE order of Saurians is composed of reptiles more diversified in 

 their external appearance than that of the Ophidians, which we have 

 just passed in review; even more diversified than the Batrachians, 

 which were introduced at the head of this report. 



In all the Saurians the body is generally elongated and rounded, to 

 a few exceptions; its surface is covered with scales or modifications of 

 scales, which are subjected to a great diversity of forms and aspects, 

 from true imbricated scales down to minute granules. The eye is 

 provided, in the majority of cases, with distinct eyelids. The auricular 

 aperture, likewise, is visible externally in most of them, so as to ex- 

 pose the tympanum or drum. The mouth is not dilatable, as in the 

 Ophidians ; the jaws being toothed, and the palate occasionally also, 

 though we never observe any fangs or venom in the whole order of 

 Saurians. Some of them are, however, considered as highly venemous, 

 and hence dangerous, by the natives of various regions of the globe : 

 a prejudice which is difficult to eradicate from their mind. Indeed, 

 such saurians as are truly dangerous to men, become such by their 

 large size and strength, and those who are familiar with the alligators 

 and crocodiles will readily understand our meaning. The limbs are 

 generally four in number ; sometimes two only being observed, some- 

 times in a rudimentary state, so as to be hidden under the skin, ap- 

 pearing completely deprived of them. The tail is elongated, tapering, 

 seldom prehensile, covered with scales mostly disposed upon' verticils ; 

 the cloaca, situated at the base of that organ is generally transverse. 



Upon the skeleton we observe distinct and moveable ribs, also a 

 sternum, which Ophidians have not. The external envelope of the 

 eggs consists in a tough or hard membrane ; the young undergoing no 

 metamorphosis. 



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