236 



REPTILIA 



CLASS III 



quadrant of arc, so that the pubic symphysis 

 is formed by the lateral faces irfstead of 

 extremities of the bones. Upper Jura; 

 "Wyoming and Colorado. 



Apafosaurus, Marsh. Upper Jura ; 

 Colorado. PUurocoelus, Marsh. Lower Cre- 

 taceous ; Maryland. 



Omithojms, Seeley (Pelorosaurus, Mantell ; 

 Eiicamerotus, Hulke ; Chondrosteosaurus, Both- 

 riospondylus, Owen), (Fig. 334). Cervical 



Fir;. 339. 



Diplodocus lonyus, Mar.sh. Upper Jura ; Canon City, Colorado. 



Skull, Vs (after Marsh). 



vertebrae elongated, dorsals Avith expanded 

 neural canal. Fragmentary remains of large 

 size frequent in the Upper Jura and Wealden 

 of England. 0. hidkei, Seeley. 



Titanosaurus, Argyrosaurus, Lydekker. 

 Supposed Cretaceous of Patagonia. 



Family 2. Diplodocidae. Marsh. 



Teeth slender and cylindrical, confined to 

 front margin of the jaws. External narial 

 opening small, unpaired, placed at apex of the 

 shdl Caudal vertebrae elongated, ventrally 

 excavated ; chemvn bones double posteriorly, each 

 having both anterior and piosferior branches. 

 Upper Jura. 



Diplodocus, Marsh (Fig. 339). Total 



