'198 SAURIA. 



all terminated by curved nails. The head, which has the shape of a 

 quadrangular pyramid, is flattened, tapering forwards, covered with 

 horny, polygonal, and symmetrical plates. The tympanum is visible, 

 and placed either evenly with the surface of the head, else slightly 

 within the edge of the auricular aperture. The eyes, in most instances, 

 are provided with three movable lids. The mouth is deeply cleft, 

 with the labial plates and inframaxillary shields considerably deve- 

 loped. The teeth are unequal in size and shape, inserted upon the 

 inner edge of a common groove, situated along the exposed portion of 

 the maxillary bones, the palatine teeth being either wanting or pre- 

 sent, and, in the latter case, varying in position. The tongue is free, 

 fleshy, flattened, thin, more or less protractile ; its base being occasion- 

 ally surrounded by a sheath; its surface covered with scale-like, 

 rounded, or angular papillae ; its extremity always emarginated or 

 bifurcated, subdivided into two equal parts. The tail is conical, very 

 long, generally rounded upon its whole extent, and protected by ver- 

 ticillated scales. The skin is covered with scales varying in size, 

 granular or rhomboid, and keeled on the dorsal region, which is never 

 crested. The neck exhibits, in most instances, one or several cross- 

 folds, covered with tubercles, granulations, or large scales, varying in 

 shape, constituting a kind of necklace. The abdomen is protected 

 with scutellae, always larger than the dorsal scales ; they are either 

 rectangular or rounded. In most cases, pores may be observed along 

 the thighs or upon the interfemoral region. 



SYN. Lacertiens, Ccv. Rdgn. Anim. II, 1817. DUM. & BIBR. Erpet. gen. V, 1839, 1. 



Lacertae, WIEGM. Herp. Mfex. I, 1834, 9. 



Lacertidae, BONAP. Saggio, Distr. Anim. Verteb. 1831. 



Autosaures, DUM. & BIBR. Erpet. gen. V, 1839, 1. 



It has been observed that in some Lacertians the root of the teeth is 

 hollow, whilst in others the teeth are compact throughout. This fact 

 has led some authors to consider each of these groups as constituting 

 a separate family, whilst others have looked upon them as indicating 

 a subdivision of a rather minor degree. 



Of each of these two subdivisions, the collection made by the Ex- 

 ploring Expedition contains but one species, which we will introduce 

 1 to the reader under their special headings. 



