ORDER Vir CROCODILIA 215 



reduced. Supratempm'al vacuities very large. Dermal armour completely obsolete ; 

 limbs paddle-shaped. Middle and Upper Jura. 



Metriorhynchus, v. Meyer. Skull elongated and tapering, feebly sculptured. 

 Prefrontals unusually large and forming an overhanging ledge above the orbits. 

 External nostril large, upwardly directed ; teeth slender, carinated, and slightly 

 curved, twenty to twenty-seven present on either side of the jaws above and 

 below ; three or four anterior teeth enlarged. Fore-limbs much smaller than 

 the hinder pair. Middle Jura. France and England. 



Geosaurus, Cuvier (Cricosaurus, Wagner ; lihacheosaurus, von Meyer). 

 Lithographie Stone ; Bavaria. Siichodus, Lydekker. Oxford ian ; England. 

 Plesiosuchus, Owen. Kimmeridgian ; Dorsetshire. 



Dakosaurus, Quenst. Skull comparatively short and broad ; nasals reach- 

 ing the premaxillae ; snout compressed and rounded in front. Teeth large, 

 slightly curved, oval in section, smooth, with anterior and posterior carinae : 

 about twenty on each side of the jaw above and below. External cranial 

 bones smooth or feebly sculptured ; mandibular rami without lateral vacuity. 

 Middle and Upper Jura ; Swabia and Bavaria. Kimmeridgian ; England. 

 A complete skeleton of D. maximus, Quenst., 4 m. long, preserved in the 

 Stuttgart Museum. 



Family 3. Pholidosauridae. 



Siiout long and narrow, passing ahruptly into the facial region. Orbits oval, 

 laterally placed, almost as large as the supra temporal vacuities, and confluent with the 

 lateral temporal fossae. Nasals long and narrow, reaching the posterior tip of the 

 elongated preinaxillae. Prefrontals of moderate size. Internal narial opening 

 bor der ed laterally by the pterygoids. Dorsal aml ventral armour present. 



The members of this family are known only from fresh-water deposits of 

 the Purbeckian, Wealden, and Lower Cretaceous. 



Pholidosaurus, v. Meyer {Macrorhynchus, Dunker). Teeth round or oval in 

 section, longitudinally striated, in uniform series of about thirty on each side 

 in either jaw. Wealden of England and Neocomian (Hils Sandstone) of 

 Hanover. 



Petrosuchus, Owen. Like the preceding, but internal narial opening 

 enclosed by the palatines. Purbeckian ; Dorsetshire. 



Hylaeochampsa, Owen. Imperfectly known. Wealden ; England. 



Section 2. Brevirostres. Lydekker. 



Snout short, broad, and rounded. Nasals usually reaching the p-emaxillae and 

 external nostril. Dentary alone forming the shmi Symphysis of lower jaw ; teeth 

 irregidar in size and shape. Vertebrae amphicoelous. 



Family 1. Atoposauridae. 



Small, lizard-like crocodiles with broad, triangulär shulls. Orbits much larger 

 than supratemporal vacuities. Dorsal armour consisting of a paired longitudinal 

 series of oblong plates. No ventral armour observed. Upper Jura. 



Alligatorium, Jourdan. Total length about 40 cm. External cranial 

 bones coarsely sculptured; bind -limbs longer and more robust than the 

 anterior pair. " Lithographie Stone ; Cerin, France, and Bavaria. 



