SAURIA. 279 



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

 Snakes, and more particularly the Orvets {Anguis), wilh \yliich 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 shglitly extensible and notched ; and the jaws 

 are armeil all round with small serrated teeth. The remainder of their conformation approximates 

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

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

 Gray) have no teeth to the palate. 



The Seps {Sejis, Dand.) — 

 IMerely 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 ditTers from Seps by the total absence of anterior limbs, merely re- 

 taining tlic 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 hands on the tail, like those of ordinary Lizards. 



Some have a 2;roove along each side of the trunk, and the tympanum still very apparent. They approximate 

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

 Others have a concealed tympanum, and conduct to the Chirotes, aud thence to the Anipliisbai'ues. 



The Chirotes {Cliirotefi, Cuv.) — 

 Resemble the last l)y their veiticiUated scales, and still more tlic Am[)hisbfcncs, 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. lumbncoides) inhabits Mexico, and has all tlie internal organization of an Amphisbacne, with 

 femoral pores, and one g:reat lung and the vesti^^e of a second, as in most Opiiidians. 



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 Anguh; but among the fossils 

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

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

 articulations, winch form in the aggregate a sort of fin or swimming-paw, analogous to those of Ce(a- 

 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 javvs armed with 

 conical teeth, inserted in a groove. 

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



The otiier genus, or 



The Plesios.vurus, — 



Had a small head, and extremely long serpent-like neck, composed of more cervical vcrtebrie 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 knowdedge of which we are principally indebted to the researches of Messrs. 

 Home, Conybcare, 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 il. Fitzinger, since neither their tongue 

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

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

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



