5 6o 



MANUAL OF ZOOLOGY. 



described, from the Jurassic deposits of North America, a 

 Reptile, which he has named Sauranodon, and which agrees 

 in all important respects with Ichthyosaiirus, except that it has 



Fig. 312. A, Pectoral arch and fore-limbs of Ichthyosaurus: a Interclavicle ; b b 

 Clavicles ; c c Scapulae ; d d Coracoids ; e Humerus ; f Radius ; g Ulna. (Some- 

 what altered from Huxley.) B, Pelvis of Ichthyosaurus : p Pubis; il Ilium; is 

 Ischium. 



no teeth. Prof. Marsh regards it as the type of a new order, 

 but we may in the meanwhile include it here. There is no 

 doubt whatever but that the Ichthyosauri were essentially 

 marine animals, and they have been often included with the 

 next order (Sauropterygid) in a common group, under the name 

 of Enaliosauria or Sea-lizards. 



In the biconcave vertebras and probable presence of a ver- 

 tical tail -fin, the Ichthyosaurus approaches the true fishes. 

 There is, however, no doubt as to the fact that the animal was 

 strictly an air-breather, and its reptilian characters cannot be 

 questioned, at the same time that the conformation of the limbs 

 is decidedly Cetacean in many respects. Much has been 

 gathered from various sources as to the habits of the Ichthyo- 

 saurus, and its history is one of great interest. From the 

 researches of Buckland, Conybeare, and Owen, the following 

 facts appear to be pretty well established : That the Ichthyo- 

 sauri kept chiefly to open waters may be inferred from their 

 strong and well-developed swimming apparatus. That they 

 occasionally had recourse to the shore, and crawled upon the 

 beach, may be safely inferred from the presence of a strong 

 and well-developed bony arch, supporting the fore-limbs, and 

 somewhat resembling in structure the scapular arch of the Or- 

 nithorhynchus or Duck-mole of Australia. That they lived in 



