VIII 



PROSAURI — rkOTOROSAURI 29 I 



tions, which are arranged in many transverse or rather clievron- 

 shaped rows, still greatly resembling the condition prevailing 

 in the Miorosauri, except that they have sunk deeper into 

 the skin, being no longer directly covered by the scales. The 

 skull, being no longer completely encased by bones, and possessing 

 now wide supra- and infra-temporal fossae, appears at tirst sight 

 much like that of a generalised lizard, except that it possesses 

 three very conspicuous and distinct arcades in the temporal region : 

 namely, the orbito-squamosal bridge across the temporal fossa, 

 formed by the postorbital and squamosal ; the arch formed 1 )y 

 the squamosal with the postero-lateral buttress of the jjarietal ; 

 and the infratemporal arch or jugal bridge. The jugal itself is 

 long, connecting the quadrato-jugal with the maxillary and 

 lacrymal, and sending up an ascending process to the postorbital 

 bone, thus taking a considerable share in the formation of the 

 orbit. The quadrato-jugal is small, apparently fused with the 

 quadrate, which itself is tirraly overlaid by the squamosal. The 

 quadrates are further fixed by being buttressed by the pterygoids, 

 which rest . upon short basisphenoid processes and extend far 

 forwards, meeting the vomers and separating the palatines. The 

 premaxillae are short, the nares small and terminal, the nasal 

 bones are large. There is a small interparietal foramen. The 

 teeth are acrodont and pointed, forming unbroken series on the 

 premaxillaries, maxillaries, palatines and dentaries, and there are 

 scattered little teeth on the vomers. 



PalaeohaUcria longicauclata from the Lower Eed Sandstone of 

 Saxony. Total length about 18 inches, with six cervical, twenty 

 trunk, three or four sacral, and about fifty caudal vertebrae. The 

 teeth are ankylosed with the supporting bones. The five fingers 

 have 2, 3, 4, 5, 3 phalanges respectively. For the skull see Fig. 

 54, G, p. 2(S0. Tderpeton elginense from the Triassic sandstone 

 of Scotland, and perhaps Saurostenion of the South African 

 Karroo sandstone seem to be allied. 



Frotorosaurus {irpoiro^ = first, oypa = spring, or dawn, not 

 Proterosaurvs) apparently several species, e.g. P. lincJci in the 

 Upper Permian (marl-slate and magnesian limestone) of Thuringia 

 and Durham. About 4 or 5 feet long, and in its general appear- 

 ance rather like a Monitor -lizard, with about eight cervical 

 vertebrae, most of which carry slender backwardly-pointing ribs, 

 sixteen long-ribbed trunk-vertebrae, followed by three or four 



