GENERAL STRUCTURE AND ORDERS. 



1035 



known Dasycefis, from the English Permian, is allied in cranial 

 structure to Anthracosaurus. Moreover, some writers place in this 

 family the imperfectly known genera Platyops, from the Permian 

 of Russia, and Macromerion, from the corresponding strata of 

 Bohemia. 



Family Mastodonsaurid^e. — The members of this family, to- 

 gether with some of the Anthracosauridce, constitute the Euglypta 

 of Professor Miall's classification, and may be regarded as the 

 typical representatives of the order. They are distinguished 

 from the latter family by the still more complex structure of the 

 teeth ; the stronger sculpture of the skull • and the absence of 

 scutes on the ventral . surface of the body. Large palatovomerine 

 teeth (fig. 966) are placed on the inner side of the maxillary 

 teeth, and there is a corresponding inner series of small teeth in 



Fig. 966. — Palatal aspect of the cranium 

 of Mastodonsaurus giganteus; from the 

 Keuper of Wiirtemberg. Reduced. (After 

 Miall.) 



Fig. 967. — Mastodonsaurus 

 giganteus. a, Dorsal aspect 

 of skull, greatly reduced ; b, 

 tooth on a larger scale. 



the mandible ; while there is no bony ring in the sclerotic. The 

 following features may be also noticed, although some of them are 

 common to the typical Anthracosauridce. The mandible has a 

 large postglenoidal process, and the crowns of the teeth are conical. 

 The palatines have the same position as in the Archegosauridce. In 

 the pelvis of the type genus the pubes are separate from the ischia, 

 and do not enter into the formation of the acetabulum ; and the 

 sacral ribs form kidney-like disks. The centra or bodies of the ver- 

 tebrae in the adult form disks which are fully ossified ; but in the 



