THE YEAR'S VERTEBRATE PAL/EONTOLOGY 519 



The list of rh^'nchocephalian reptiles has been increased 

 by Dr. R. Broom's description (Trans. S. African Phil. Soc, 

 vol. xvi. p. 379) of the new genus Palacrodon hroivni, from 

 the Triassic division of the Karoo series of South Africa. 

 Dr. Broom, it may be added, restricts the Rhynchocephalia 

 to reptiles with a radiating pelvis, and therefore excludes the 

 Indo-European Triassic genera Pala^ohatteria, R/iync/wsaurits, 

 and Hypcrodapcdon^ in which the pelvis is plate-like. On this 

 view, Palacrodon is the only Triassic representative of the order. 



During the year important work has been accomplished in 

 that remarkable group of Permian reptiles known as the Pelyco- 

 sauria. In an article published in the Bulletin of the American 

 Museum (vol. xxiii. p. 265), Prof. H. F. Osborn has given a 

 figure of the skeleton of the Texan " ship-lizard," Naosaurus 

 clavigcr, with an attempted restoration of the creature's bodily 

 form. The length of the skeleton is 6h ft. Among the more 

 striking features are the enormous head, armed with powerful 

 teeth, and the great height of the spines of the vertebrae of the 

 long back, which are furnished with transverse bars recalling 

 yard-arms, and thus suggesting the name of the genus. The 

 restoration of the allied genus Diuictrodon has been essa3^ed 

 by Dr. E. C. Case in vol. xv. of TJic Journal of Geology. 



Of far more importance is the monographic revision of the 

 Pel3xosauria by the last-named naturalist, published by the 

 Carnegie Institution of Washington. After discussing the various 

 opinions as to the proper systematic position of these reptiles, 

 the author concludes that the}- really form a subordinal group 

 of the Rhynchocephalia. They all had notochordal vertebrae, 

 with intercentra, and two-headed ribs ; but it was only in the 

 more specialised forms that the spines of the vertebrae attained 

 the characteristic development. All were carnivorous. The 

 more primitive representatives of the group, constituting the 

 new family Poliosauridae, are not far removed from the Permian 

 rhynchocephalians of the suborder Protorosauria ; but the other 

 forms display great specialisation, which to a great extent 

 obscures their rh3-nchocephalian affinities. The great develop- 

 ment of the dorsal spines of the vertebrae is the most obvious 

 feature of this specialisation, but it is accompanied by others 

 such as the roofing over of the upper temporal fossa, the mode 

 of rib-attachment, and the enormous size of the claws. Although 

 in earlier stages the spines may have served some useful purpose, 



