512 



ZOOLOGY. 



The Ichthyosaurs were colossal reptiles from two to thirteen 

 metres (six to forty feet) in length, swimming in the ocean by 

 four paddle-like limbs consisting of six rows of digital bones 



Fit;. 448. Skull of Ichthyosaurus ; lateral view. Pinx, premaxillary bone ; MX, 

 maxillary ; N~, nasal ; Fr, frontal ; Prf, prefrontal ; Pof, postfrontal ; Pa, parietal 

 Z, lachrymal; M, malar; Qj, quadratojugal ; Q, quadrate; Pob, postorhital ; Sq, 

 equamosal ; D. dentary; Ang, angular ; Art, articular ; 3. Ar, subarticular ; Pier 

 pterygoid. After Cope. 



the head was very large, the neck very short, and the orbits 

 were enormous ; the vertebras were remarkably short and bi- 



concave. They were carniv- 

 orous, and powerful swim- 

 mers, and common in tho Ju- 

 rassic seas of Europe ; one 

 form existed in the Jurassic 

 times in Wyoming. 



Order 7. T/ieromorpha. 

 This order is divided into the 

 Pelycosauria and Aiwmo- 

 dontia. The beaked Saurians 

 were somewhat lizard-like, but 



Fig. 449. Posterior view of the skull of wei'6 Synthetic types. COmbill- 



IchthyoKaurus ; lettering: as in Fig. 443, . 



With following additions; Bo, basiocci- lllg the Characters OI the icll- 



pital ; EJCO, Exoccipital ; Sup. 0, supra- ., ,, , ., 



occipital ; Opo, opisthotic ; Slap, supra- thyOSaurs, tllC turtles, the 



etapedial or hyomaudibnlar. After Cope. /-, 7 ; ,-, ,, a -, 



Sphenodon, with those of liz- 

 ards, Dinosaurians, and crocodiles. The skull was short, 

 and in Dicynodon the jaws in front had the nipping, horny 

 beak of a turtle, while from behind in the upper jaw pro- 

 truded two long, curved, canine teeth. Dirt/not/on lii/rici'jis 

 Owen, had a skull about half a metre (20 inches) long. 



