. Text book of zoology. Zoology. Glass 4. Beptilia. Order 4. Grocodilia. 427 For the rest, these tkr-ee groups are connected by intermediate foi-ms; there are species of Crocodiles which approach the Alligators, and a Gavial which forms a connecting link with the Crocodiles. The oldest Crocodiles known, from the Triassic {Belodon and others) are specially characterised by their resemblance to Lacertiha and Ohelonia with. Fig. 351. pterygoid. A Skull of a Gavial, Bof a Teleosaiirus. n' internal nares, p palatine, v respect to the position of the internal nares; the palatines and pterygoids do n
. Text book of zoology. Zoology. Glass 4. Beptilia. Order 4. Grocodilia. 427 For the rest, these tkr-ee groups are connected by intermediate foi-ms; there are species of Crocodiles which approach the Alligators, and a Gavial which forms a connecting link with the Crocodiles. The oldest Crocodiles known, from the Triassic {Belodon and others) are specially characterised by their resemblance to Lacertiha and Ohelonia with. Fig. 351. pterygoid. A Skull of a Gavial, Bof a Teleosaiirus. n' internal nares, p palatine, v respect to the position of the internal nares; the palatines and pterygoids do not form a canal, but the internal nares open much farther foi-ward than in those now living. The Crocodiles from the Jurassic, and some of those from the Cretaceous formations [Teleosaiirus [Kg. 351 5], etc.) approach the extant fonns in this respect; for the palatines, but not the pterygoids, are connected to form a canal, and the nares are thus moved much further back. All these- older forms difEer also from those of to-day in the possession of biconcave vertebrae. On the other hand the Tertiary and some of the Cretaceous forms- exactly resemble those now existing; the pterygoids take pai-t in the formation of the nasal canal, and the centra are procoelous. The Crocodiles of different periods afford a very interesting series. Whilst many extinct Reptiles, , the Crocodiles just mentioned,, as well as many others, are allied to the orders of the present day, there are also many forms constituting orders which are without living representatives. Several of these groups are of considerable interest, and the most important will now be briefly considered. The Ichthyosaurians occupy a position among the Reptiles similar to that of the Whales among Mammals, and they are very suggestive of this group. The. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may
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