order vn CROCODILIA 215 



reduced. Supratemporal vacuities very large. Dermal armour completely obsohh . 

 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; Rhacheosaurus, von Meyer). 

 Lithographic Stone; Bavaria. Suchodus, Lydekker. Oxfordian ; England. 

 PlesiosuchuSj Owen. Kimmeridgian ; Dorsetshire. 



Ddkosaurus, 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 crania] 

 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. 



Snout long and narrow, passing abruptly into the facial region. Orbits oval, 

 laterally placed, almost as large as the supratemporal vacuities, and confluent with the 

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

 elongated premaxillae. Prefrontals of moderate size. Internal narial opening 



bordered laterally by the pterygoids. Dorsal and rent rat 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. AVealden ; England. 



Section 2. Breyirostres. Lydekker. 



Snout short, broad, and rounded. Nasals usually reaching the premaxillae and 

 externa] nostril. Dentary alone forming the short symphysis of lower jaw ; teeth 

 irregular in size mid shape. Vertebrae amphicoelous. 



Family 1. Atoposauridae. 



Small, lizard-like crocodiles with broad, triangular si- a I Is. Orbits much larger 

 than supratemporal vacuities. Dorsal armour consisting of a poind longitudinal 

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



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

 bones coarsely sculptured : hind-limbs longer and more robust than the 

 anterior pair. Lithographic Stone : Cerin, France, and Bavaria. 



