Professor Owen on Brituh Foml Reptiles, 73 



111 the place of the Goniopholis and Suchosaurus, the crocodi- 

 lian genera, Steneosaurus and Teleosatirus, with the sub-genera 

 ^lodoti, Afydriosaurus, Macrospondylm, &;c. (separated, per- 

 haps, without sutficient reason, from the first two typical 

 genera of amphiccelian crocodiles), make their appearance in 

 the oolitic strata, especially in the lower divisions. The long 

 and narrow snouts, sharp and slender teeth, short fore-limbs, 

 and imbricated scutation of these extinct crocodilians, attest, 

 with their vertebral structure, their adaptation to an aquatic 

 life, and to the capture of a prey not more highly organized 

 than fishes. 



Some small species of crocodilians and lacertians have 

 left a few bones of their extremities in the oolitic slate of 

 Stonesfield ; and a most singular order of reptiles now makes 

 its appearance, the skeleton of which exhibits a modification 

 of the lacertian type of structure closely analogous to that by 

 virtue of which the mammalian bat is endowed with the 

 powers of fligl\t. The flying dragons, called Pterodacti/lu 

 were of small size, and are restricted, like the Teleosauri and 

 Steneosauri^ to the oolitic group. All the other genera are 

 continued into the Wealden, — the Foikilopleuron and Megalo- 

 sauriiSy by identical species, — the other genera by species 

 which are distinct from those of the oolite. The Plesiosaurus 

 and Ichthi/osmirus, existed, as we have seen, as late as the de- 

 position of the chalk. The analogy between the extinct rep- 

 tiles and fishes, in regard to the great proportion of genera 

 which are common to the Wealden and oolite, and the small 

 proportion which is continued into the cretaceous formations, 

 ofi^ers a valuable corroboration of the subordinate character 

 of the Wealden group as a member of the great oolitic series. 



No species or genus of saurian, represented by fossils from 

 the oolite, has yet been discovered in older or lower strata in 

 the British Islands. The Bysostetis is apparently confined to 

 the bone bed under the lias, which may be regarded as the 

 oldest member of the oolitic series in these islands. 



The reptiles of the Poikilitic strata exhibit deviations from 

 the typical structure of the recent families, together with oscu- 

 lant characters joining groups now distinct, as great and even 

 more anomalous than occur in any of the preceding extinct 

 genera. 



