218 EXTINCT ORDERS OF REPTILES. 



upon the beach, may be safely concluded from the presence 

 of a .strong and well-developed bony arch, supporting the fore- 

 limbs, and closely resembling in structure the scapular arch 

 of the Ornithorhynchus or Duck-mole of Australia. That they 

 lived in stormy seas, or were in the habit of diving to con- 

 siderable depths, is shown by the presence of a ring of bony 

 plates in the sclerotic, protecting the eye from injury or pres- 

 sure. That they possessed extraordinary powers of vision, 

 especially in the dusk, is certain from the size of the pupil, 

 and from the enormous width of the orbits. That they were 

 carnivorous and predatory in the highest degree is shown by 

 the wide mouth, the long jaws, and the numerous, powerful, 

 and pointed teeth. This is proved, also, by an examination 

 of their petrified droppings, which are known to geologists as 

 " coprolites," and which contain numerous fragments of the 

 scales and bones of the Ganoid fishes which inhabited the 

 same seas. 



Order VI. Sauropterygia, Owen (= Fksiosauria, Hux- 

 ley). — This order of extinct reptiles, of which the well-known 

 Plcsiosaurus may be taken as the type, is characterised by 

 the following peculiarities : — 



The hodi/, as far as is hi07vn, ivas naJced, and not furnished 

 ivith any horny or tony exoskeleton. The bodies of the vertebra; 

 ivei^e either fiat or only slightly cupiJed at each end, and, the 

 neural arehes were anchylosed with the centra, and did not 

 remain distinct during life. The transverse ^processes of the 

 vertcbrm %vere long, and the anterior trunk-ribs had simple, not 

 bifurcate, heads. No sternum or sternal ribs are known to 

 have existed, hut there were false ahdominal ribs. The neck 

 (fig. 567) in most was greatly elongated, and composed of 

 numerous vertcbrm. The sacrum ivas coni2)osed of two vcrtebrcc. 

 The orbits ivere of large size, and there was a long snout, as in 

 the Ichthyosauri, but there was no circle of bony plates in the 

 sclerotic. The limbs agree with those of the Ichthyosauri in 

 being in the form of swimming -paddles (fig. 568), but differ in 

 not possessing any supernumerary marginal ossicles. The pec- 

 toral arch consisted of a large coracoid and scapula on each 

 side, while clavicles and an interclavicle loere sometimes present, 

 but at other times apparently loanting. The teeth were simple, 



