513 



ZOOLOGY. 



The Ichtliyosaurs were colossal reptiles from two to thirteen 

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

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



Fig. 448.— Skull of Tchihyosauru? ; lateral view. Pmx, premaxillary bone ; Mx, 

 maxillary ; jV, nasal ; Fr, frontal ; Prf, prefrontal ; Pof, postfrontal ; />«, parietal ; 

 X, lachrymal ; M, malar ; Qj, quadratojugal ; Q, qua'drate ; Pob^ postorbital ; Sq, 

 squamosal ; D, dentary ; Ang, angular ; Art, articular ; S. 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 the Ju- 

 rassic seas of Europe ; one 

 form existed in the Jurassic 

 times in Wyoming. 



Order 7. TheromorpJia. — 

 This order is divided into the 

 Pelycosauria and Anomo- 

 dontia. The beaked Saurians 

 were somewhat lizard-like, but 

 were synthetic types, combin- 

 ing the characters of the Ich- 

 tliyosaurs, the turtles, the 

 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. Dicynodon fic/rireps 

 Owen, had a skull about half a metre' (30 inches) long. 



Fig. 449.— Posterior view of ttie skull of 

 IchtKyomuriis ; lettering as in Fig. 443, 

 with following additions ; Bo, basiocci- 

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

 occipital ; Opo, opisthotic ; Stap, supra- 

 stapedial or hyomandibnlar. — After Cope. 



