U30 



CLASS REPTILIA. 



morpha of the Squamata, appears to approximate in structure to 

 the femur of Ichthyosaurus campylodon^ and may therefore really 

 belong to this order. 



Order V. Proterosauria. — The genus Proterosaurus, from the 

 Middle Permian of Thuringia, is regarded by Professor Seeley as 

 presenting such peculiar features that it is entitled to ordinal dis- 

 tinction, although Dr Baur would include it in the Rhynchocephalia. 



The skull is very imperfectly 

 known, and although Professor 

 Seeley has attempted its restora- 

 tion, Professor Credner points 

 out that the specimens scarcely 

 justify the figure. There is some 

 doubt as to the mode of attach- 

 ment of the teeth to the jaws, 

 but they appear to have been 

 anchylosed to the bone, with 

 cavities beneath them, and were 

 not, as has been supposed, 

 implanted in distinct alveoli. 

 Teeth also occur on the pala- 

 tine, pterygoid, and vomer; and 

 Professor Seeley considers that 

 the palate was closed. The 

 dorsal vertebrae are amphiccel- 

 ous, and have no intercentra ; 

 but the cervicals appear to have 

 been opisthoccelous, and are re- 

 markable for their length. There 

 were intercentra in the anterior 

 cervical region. In all the ver- 

 tebrae the arches were anchylosed 



to the centra ; while in the dor- 

 Fig. 1034. — Dorsal aspect of the left pelvic , ■, -, • i , • 

 limb of Baptanodon nutans ; from the Upper SalS the COStal articulation IS 

 Jurassic of North America. Reduced. T, 

 Tibia ; i, Fibula ; F, Bone representing the 

 pisiform of the manus ; t, Tibiale ; c (left side), 

 Intermedium ; c (right side), Fibulare ; f, Un- 

 determined bone. The two bones beneath the divided neural spines. Abdom- 



placed unusually high. The 

 posterior caudal vertebrae have 



intermedium are the centralia. 

 and Hulke.) 



(After Marsh 



of the Rhynchocephalian type. 



inal ribs were fully developed 



(fig. 1035), and were apparently 



It has been suggested that the 



ilium may have had a preacetabular production ; but the pectoral 

 girdle seems to have been of the Rhynchocephalian type, the 

 clavicles and interclavicle, according to Dr Credner, closely resem- 

 bling those of Sphenodon. 



According to Dr Baur there are two centralia in the carpus ; 



