CR0C0DII.1A 271 



Order IX.— CrOCODILIA. 



Char. — Teeth in a single row, implanted in distinct sockets ; 

 external nostril single and terminal or sub-terminal. 

 Anterior trunk vertebrae with par- and di-apophyses, 

 and bifurcate ribs ; sacral vertebrae two, each supporting- 

 its own neural arch. Skin protected by bony, usually 

 pitted plates. 



Sub- Order 1 . — AMPHICCELIA.* 



Crocodiles closely resembling in general form the long and 

 slender-jawed kind of the Gauges called " gavial " or " gharrial," 

 existed from the time of the deposition of the lower lias. 



Their teeth were similarly long, slender, and sharp, adapted 

 for the prehension of fishes, and their skeleton was modified 

 for more efficient progress in water by the vertebral surfaces 

 being slightly concave, by the hind limbs being relatively 

 larger and stronger, and by the orbits forming no prominent 

 obstruction to progress through water. From the nature of 

 the deposits containing the remains of the so-modified croco- 

 diles, they were marine. The fossil crocodile from the Whitby 

 lias, described and figured in the Philosophical Transactions, 

 1758, p. 688, is the type of these amphiccelian species. They 

 have been grouped under the following generic heads : — Teleo- 

 saurus, Steneosaurus, Mystriosaurus, Macrosponclylus, Masso- 

 spondylus, to which must be added Pcecilopleuron, Pelagosaurus, 

 jEolodon, Suchosaurus, Goniopholis. 



Species of the above genera range from the lias to the chalk 

 inclusive. 



Suchosaurus of the Wealden is characterized by the com- 

 pressed crown and trenchant margins of the teeth ; Goniopholis, 

 of the Purbeck beds, by some of the dermal scales having the 

 same peg-and-pit interlocking as in the scales of the ganoid 

 fish in fig. 52. 



* Amplti, both ; koilos, hollow; the vertebra being hollowed at both ends. 



