SAURIA. 279 



Some have a spindle-shape; and others, which are nearly cyhndrical, and more or less elongated, resemble 

 Snakes, and more particularly the Orvets {Anguis), with which they have many internal points of rela- 

 tionship, and which thus grade from the family of Iguanas by an uninterrupted series of transitions. 

 For the rest, the tongue of this genus is fleshy, and but slightly extensible and notched ; and the jaws 

 are armed all round witli small serrated teeth. Tlie remainder of their conformation approximates 

 more or less to that of the Iguanas and Lizards, and all their toes are unguiculated and free. Certain 

 species have palatal teeth, and a dentelated anterior border to the tympanum, while others (the Tiliqv.a, 

 Gray) have no teeth to the palate. 



The Seps {Seps, Daud.) — 

 Merely differ from the Scinques by having the body still more elongated, almost like that of an Orvet, 

 and the feet still smaller, the fore and hind being also more separated from each other. Their lungs 

 begin to exhibit some irregularity. 



The Dipodes {Bipes, Lacep.; — 

 Compose a small genus, which only differs from Seps by the total absence of anterior limbs, merely re- 

 taining tlie scapulars and clavicles buried beneath the skin, and the hind feet alone being visible. There 

 is but one step from them to the Orvets. Some have a range of pores on each side of the anus, which 

 is not found in others. 



The Chalcides {Chalcis, Daud.) — 

 Are very elongated and snake-like Lizards, like the Seps ; but their scales, instead of being disposed 

 tile-fashion, are rectangular, and form transversal bands on the tail, like those of ordinary Lizards. 



Some have a groove along each side of the trunk, and tlie tympanum still very apparent. Tliey approximate 

 the Cordyles, as tlie Seps do to tlie Scinques, and lead, in a variety of ways, to the Pseudopodes and Opliisaurs. 

 Others have a concealed tympanum, and conduct to the Chirotes, and tlience to the Ampliisbsenes. 



The Chirotes {Chirotes, Cuv.) — 

 Resemble the last by their verticUlated scales, and still more the Amphisbsenes, by the obtuse form of 

 the head ; but are distinguished from the former by the absence of hind feet, and from the latter by 

 the existence of fore-feet. 



The only species (C. lumbricoides) inhabits Mexico, and has all tlie internal organization of an Amphisbaene, with 

 femoral pores, and one great lung- and the vestige of a second, as in most Ophidians. 



In fact, the genera which terminate this order of Saurians interpose in so many ways between the 

 ordinary Saurians and the genera placed at the head of the Ophidians, that many recent naturalists 

 object to separating the two orders, or at least establish one comprised of the Saurians in part, detaching 

 the Crocodiles, and another of the Ophidians pertaining to the family of Anguis; but among the fossils 

 of the ancient limestone formations are found two very extraordinary extinct genera, which, with the 

 head and trunk of a Saurian, have feet borne on short limbs, and composed of a multitude of little 

 articulations, which form in the aggregate a sort of fin or swimming-paw, analogous to those of Ceta 

 ceans. The first of these genera, or that of 



The Icthyosaurus, — 

 Had a large head and short neck, enormous eyes, middle-sized tail, and elongated jaws armed with 

 conical teeth, inserted in a groove. 

 Several species are found in England, France, and Germany, some of immense size. 



The other genus, or 



The Plesiosa"urus, — 

 Had a small head, and extremely long serpent-like neck, composed of more cervical vertebrae than that 

 of any other known animal. Its tail was short, and its remains are found in the same calcareous strata. 



These two genera, for a knowledge of which we are principally indebted to the researches of Messrs. 

 Home, Conybeare, Buckland, &.C., were inhabitants of the sea. They should form a very distinct family, 

 but what is known of their osteology approaches more to that of the ordinary Saurians than the Croco- 

 diles, with which latter they have been gratuitously associated by ^I. Fitzinger, since neither their tongue 

 nor scales are known, which are the two most distinctive characteristics of the Loricafa. [It has since 

 been ascertained that they were covered merely with skin, apparently as in the Batracliians ; and there is 

 reason to suspect that the Icthyosaur possessed a cartilaginous dorsal fin, as in many of the true Ceiacca ] 



