513 



ZOOLOOT. 



The Ichthyosaurs were colossal reptiles from two to thirteen 

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

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



Fig. 448.— Skull of Ichthyosaurus ; lateral view. Prnx, premaxlllary bone ; Mx, 

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

 i, lachrymal ; M, malar ; Qj, quadratojugal ; Q, quadrate ; Pob, postorbital ; Sg, 

 squamosal ; D, dentary ; Ang, angular ; AH, articular ; 8. Ar, subarticular ; Pter 

 pterygoid. — After Cope. 



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

 were enormous ; the vertebrse 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. Theroniorpha. — 

 This order is divided into the 

 Pelycosauria and Anomo- 

 dontia. Tho beaked Saurians 

 were somewhat lizard-like, but 

 Fig. 449.— Posterior view of the skull of were Synthetic tvpes, combin- 



Ichthyonaurus ; lettering as in Fig. 443, . .'' •' ^ 



witti following additions ; Bo, basiocci- ing the characters 01 the ich- 



pital ; Exo, Bxoccipital ; Sup. O, supra- ,-, ., . ^, ,, 



occipital ; Opo, opisthotic ; stap, supra- tnyosaurs, the turtles, the 



stapedial or hyomandibular. — After Cope. 07 7 -ii j_i £ t 



iSphenodoti, 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 Hgriceps 

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



