34 THE HISTORY OF THE PEEYCOSAURIA, WITH 



RhophalodonMcke, distinguished by the structure of the temporal region of the skull, 

 which has a median crest in the former, and is roofed over on the superior surface in the 

 latter. In the former the incisor teeth are strongly developed; in the latter serrated, 

 lanceolate molars are strongly developed behind the canines. 



Deuterosaurus. 



Has the skull compressed from side to side, with large transversely compressed 

 incisor teeth. The lachrymal bone is greatly developed. The postorbital arch is deep, 

 and situated below the orbit. The quadrate hone is large and developed below the 

 foramen magnum on the type of Placodus. The vertebrae are biconcave. The ribs are 

 long. The sacral ribs are well developed. Tin; scapula is expanded at its free end. 

 The pubis and ischium diverge from below the acetabulum; there is a supra-acetabular, 

 articular wedtjc on the ilium. 



'6' 



Rhophalodon. 



Has the skull more elongate and less deep, with the superior temporal vacuities 

 roofed with hone. The orbit is relatively far back and defended with a circle of sclerotic 

 bones. The incisors are clearly evidenced. The canines are large. The lanceolate 

 molar teeth are of the Megalosaurian type. The vertebrae are biconcave. The scapula 

 is concave on its borders, without conspicuous expansion at the free end. The pubis and 

 ischium do not manifestly diverge ventrally, there may be a supra-acetabular articulation 

 on the ilium." 



PEEYCOSAURIA FROM THE PERMIAN OF BOHEMIA. 



In the first volume of the Fauna of the Gascoal, Fritsch 61 described a, specimen 

 that he supposed to be a portion of the border of the pectoral fin of a fish. Later in a, 

 supplement to the third volume of the same work 02 he recognized the nature of the sup- 

 posed spine and described it as the neural spine of new species of Cope's genus NaoSaurus, 

 N. mirabilis. This is the oidy reptile from the Permian deposits of the Bohemian 

 region. 



In 1895 Fritsch 153 described new forms from the same horizon. A figure of a 

 dorsal vertebra and spine of the same species as before described is figured. There is no 

 description beyond the statement of the length of the spine. "Diesel ben besitzen eine 

 ISfache Lange des Wirbelkorpers und erreichen eine Lange eines halben Meters." It is 

 still considered as the single reptile of the horizon. 



