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 ; 



I 



Fob 



Fig. 448. Skull of Ichthyosaurus ; lateral view. Pmx, premaxillary bone ; MX, 

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

 L, lachrymal; M, malar; Qj, quadrat oj ugal ; Q, quadrate; Pob, postorbital ; Sq, 

 squamosal ; D, dentary ; Ang, angular ; Art, articular ; S. Ar, subarticular ; Pter, 

 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. Theromorplia. 

 This order is divided into the 

 Pelycosauria and Anomo- 

 dontia. The beaked Saurians 

 were somewhat lizard-like, but 

 Fig. 449.-post"rior view of the skuii of were synthetic types, combin- 



Ichthyo*aurus ; lettering as in Fig. 443, . ., , L >i T i 



with following additions ; Bo, basiocci- mg the characters of the Icll- 

 pital ; JSjio, Exoccipital ; Sup. 0. supra- . -, , , ,-1 / -\ 



occipital ; Opo, opistiiotic ; stap, supra- thyosaurs, the turtles, tne 



stapedialorhyornandibular.-AfterCope. ^^^ 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 figriceps 

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



