SERFENTIA. 



181 



FAMILY II. 







SERPENTIA. 



THE true Serpents, which are by far the most numerous, comprise the genera 

 without a sternum, and in which there is no vestige of 

 a shoulder, but where the ribs still surround a great part 

 of the circumference of the trunk, and where the body 

 of each vertebra is still articulated by a convex surface 

 to a cavity in the succeeding one. The third eye-lid 

 and the tympanum are deficient; but the malleus of 

 the ear exists under the skin, and its handle passed 

 behind the tympanum. There is still a vestige of a 

 posterior limb, concealed under the skin, in several 

 of this family, and which in some of them shows its 



extren.ity externally in the form of a small hook. We subdivide them 



into two tribes. 



That of the AMPHISB^EN^E, as in the preceding reptiles, still has the lower 

 jaw supported by a tympanal bone directly articulated 

 with the cranium, the two branches of this jaw soldered 

 together in front, and those of the upper one fixed to the 

 cranium and to the intermaxillary bone, circumstances 

 which prevent that dilatation of the mouth which obtains 



in the succeeding tribe, and which occasions a uniformity of the head and body, 



a form which enables them to move backwards or forwards with equal facility. 



The bony frame of the orbit is incomplete behind, and the eye very small; the 



body is covered with scales, the trachea long, and the heart very far back. 



They are not venomous. 



They form two genera, one of which is allied to Chalcides and Chirotes, 



and the other to Anguis and Acontias. 



AMPHISBJENA, Linnaeus*. 



The whole body surrounded with circular ranges of quadrangular scales, 

 like the Chalcydes and the Chirotes among the Saurians ; a few conical teeth 

 in the jaws, but none in the palate. There is but one lung. 



Two species have long been known, Amph. alba, Lacep., and Amph.fuli- 

 ginosa, Lin. both from South America. They feed on insects, and are often 

 found in ant-hills, which has occasioned a belief among the people that the 

 large ants are their purveyors. They are oviparous. 



* From a/A/fi; and faiv./v, walking both ways. The ancients attributed two heads to it. 



