4jB REPTILFS. 



deficient ; but the malleus of the ear exists under the skin, and its handle 

 passes 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 extremity externally iu the form of a small 

 hook*. 



"We subdivide them into two tribes. 



That of the Amphisb^n^ (the Double Walkers), as in jhe 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 inter- 

 maxillary bone, — circumstances that prevent that dilation of the mouth 

 which obtains in the succeeding tribe, and which occalsions a uniformity of 

 the head and body, a form which enables them to move backwards or for- 

 wards with equal facility. The bony frame of the orbit is incomplete be- 

 hind, and the eye very small ; the body is covered with scales, the anus 

 is close to its extremity, 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. 



Amphisb^naI, L. 



The whole body surrounded with circular ranges of quadrangular scales, 

 like the Chalcides and the Chirotes among the Saurians ; a series of pores 

 before the anus, a few conical teeth iu the jaws, but none in the palate. 

 There is but one lung. 



Two species have long been known, Amph. alba, Lacep. II, xxi, 

 1; and Amph. fulixjinosa, L., Seb. II, xviii, 2, C. 3, and Ixxiii, 4, 

 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;]:. 



There is another in Martinique entirely blind, Amph. asca, Cuv.|| 



The Leposternon, Spix, are Araphisbaenae, the anterior part of whose 

 trunk has a collection of plates above which interrupts the rings. They 

 have no anal pores, their head is short, and their muzzle is somewhat 

 elongated §. 



* See the dissertation (German) of M. Mayer on the posterior extremities of the 

 Ophidians, in the 12th vol. des Curieux de la Nature of I3onn. 



f From the Greek words amphis and bahiein, walking hoth ways. The antients 

 attributed two heads to it. This name has been erroneously applied to some Ameri- 

 can Serpents, which it is impossible the antients could have known. 



X The Jrnph. flavescens, Pr. Max. lib. ix. 



II May it not be the A. vermicularis, Spix, XXV, 2? he says, " occuli vix con- 

 spJcui" — I can see none. He employed the same expression for his A. oxyura. 



§ Lep. mkrocephahts, Spix, or Amph. punctata, Pr. Max. 



