66 PLESIOSAURUS. 



3. Ichthyosaurus tenuirostris, Phil. Trans. 1819, t. 15. 

 Cuv. Os. Fos, V. t. 28, f. ] , t. 29, f. 8, 9, t. 28, f. 6, 7, 8. 



Muzzle long and slender ; teeth slender. 



4. Ichthyosaurus Intermedius, Cuv. Os. Fos. v. t. 29, 

 f. 2, 5. 



Teeth more acute and less deeply striated than in I. cojn- 

 rmmis, but less slender than in I, tenukostris. 



5. Ichthyosaurus grandipes. Sharp, Proceed. Geol. Soc. 

 xvi. 222. 



The vertebra three-fifths the length of its breath ; the pad- 

 dle large ; humerus one-fifth the length of the animal ; the 

 ulna or radius notched on the outer edge ; phalanges circular 



or oval. Teeth ? In the Ichth. comrmuiis, tenuirostris, 



and intermedius, the phalanges are angular. 



6. Ichthyosaurus latifrons. {Broad-headed Ichthyosaurus.) 

 Koenig, Icon. Fos. Sect. ii". t. ined. (v. iVTus. Brit.) 



Fos. Northamptonshire. 



See z\soIchthyosaiiriisuniforniis,Y\Qmm^,'QriX.. Amm. 154. 



Gen. III. PLESIOSAURUS. Conybeare. 



Caput parvum ; collum longum, vertebris numerosis ; 

 dentes in foveolis inserti. 



The head is small, about one-fifth the length of the neck, 

 with the teeth inserted in small pits. The neck is very long, 

 with about 25 vertebrae ; the body about 4 times, and the 

 tail 5 times, the length of the head. The vertebrae resemble 

 those of the Crocodiles. The paddles are longer than those of 

 the Ichthyosauri, but they may vary in the species. 



1 . Plesiosaurus dolickodeirns, [Long-necked Plesiosaurus.) 

 Guv. Os. Fos. V. t. 31. Geol. Trans, series i. t. 48. 



Fos. Lyme Regis in Com. Dorset. 



ft. Homii, Home. Phil. Trans. 1818, t. 



2. PlesiosaiLnis carinatns. Vertebris carinatis. Cuv. Os. 

 Fos. V. 486, 



Fossil in the Oolite of Boulogne. 



