ORDER VII CROCODILIA 211 



Sub-Order 2. PSEUDOSUCHIA. Zittel.i 



Premaxillae reduced ; nasals very large. External nares paired, placed far 

 forwards ; internal nares separate, in about the middle of the palate. Orbits large^ 

 laterally direded. Parietal s and front als paired ; postorbital distind. Teeth conical, 

 deeply socketed, confined to anterurr half of the jaws. Vertebrae arnphiplatyan ; 

 cervical ribs hatdiet-shaped, double -headed. Fore-limb slightly shorter than the 

 posterior ; fifth digit of pes reduced, comprising but a single phalanx. Dorsal armour 

 consisting of a paired series of oblong scutes. 



Aäosaurus, Fraas (Fig. 312). Body lizard-like, longicaudate, with dorsal 

 and ventral armouring of radially ornamented scutes ; ventral scutes smaller 

 than the dorsal, and almost Square. Skull triangulär, acuminate in front. 



Fig. 312. 



Artomurus ferrutus, Fraas. Upper Keuper ; Heslach, near Stuttgart. Head and anterior jxirtion of trank, ^U. 

 J, Orbit ; D, Anturbital vacnity ; N, Narial opening ; S, lateral temporal vacuity (alter ( ). Fraas). 



Antorbital vacuities large, separated from the large external nares by a narrow 

 ascending process of the maxilla. Posterior border of the orbits formed by 

 the postfrontal and postorbital, the inferior border by the jugal. Parietals 

 and frontals similar in form and size. Temporal region imperfectly known. 

 Mandibular rami pierced by a large foramen between the articular and angular. 

 Interclavicle blade-like. Twenty-four complete but slightly crushed in- 

 dividuals are preserved in the Stuttgart Museum, all on a single slab of 

 Stuben Sandstone (Upper Keuper), from Heslach, near Stuttgart. The largest 

 of these has a total length of 86 cm. 



Dyoplax, Fraas. Upper Keuper ; Stuttgart. Typothorax, Cope. Trias ; 

 New Mexico. 



Ornithosiichus, Newton. Skull pointed in front, very simihir to Actusaurus. 

 Orbits large, supratemporal vacuities small, the lateral ones triangulär. Teeth 

 slightly recurved, with finely serrated anterior and posterior cutting edges. 

 V'^ertebral centra elongated, with very stout neural spines. Ilium elongated, 

 ischium slender, pubis long and rod-like. Elgin Trias. 0. icoodwardi, Newton. 



E rpetosaurus, Newton. Skull narrov/ and rounded in front. Orbits sub- 

 elliptical, directed upwards and forwards. Supratemporal vacuities round, the 



^ Literat are : 



Fraas, 0., Ueber Dyoi>lax areiiaceus (Wiirtt. Jaliresh. vol. XXIII.), 1867.^Aetosaurus ferratus 

 {ihül. vol. XXXIII.), 1877.— Newton, E. T., Reptiles from the Elgin Sandstone (Phil. Trans, vol. 

 CLXXXV.), 1894. 



