192 



THE AMERICAN NATURALIST 



[Vol. XLVII 



by Cope." Possibly new discoveries of the appendicular skele- 

 ton will widen this gap and give us more definite ideas of the or- 

 ganization of what are possibly the most primitive of the known 

 Eeptilia. Similar ideas were formerly held as to the position of 

 the mammalian order Condylarthra, but further knowledge of 

 the anatomy of the skeleton of the body has convinced Dr. 

 Matthew that the group has many characters which are not at all 

 primitive and which would seem to remove the group from an 

 ancestral position. 



The Cotylosauria originated probably as early as the middle 

 Pennsylvanic, although the evidence for this is uncertain. Two 

 genera of reptile-like forms known from the Carboniferous of 

 Ohio and France, Eosauravus Williston and Sauravus Thevenin, 

 are doubtfully assigned to the order. If these are not Cotylo- 

 sauria then the order is Permian. The Cotylosaurian reptiles 

 have been found in America, Europe and Africa. There is little 

 relationship existing between the faunas of the various conti- 

 nents and the place of origin of the order is uncertain, since rep- 

 resentatives are found on both sides of the water at practically 

 the same time geologically. This same thing is true among other 

 fossil vertebrates, notably Eohippus, the Branchiosauria, the 

 Microsauria, the Embolomeri, etc. The significant conclusion is 

 reached that : 



There is no single one of the Cotylosauria that can be considered as an 

 ancestral form of the other reptiles. ... It is impossible to derive the 

 Diapsidan and Svnapsidan types from the known ( 'otylosaurs. 



The make-up of the work is excellent. The figures are many of 

 them new and all are well executed. The author has drawn on 

 published matter to the Cotylosauria and has inserted figures 

 from Cope, Broili, Williston, Boulenger, Moodie, Thevenin, von 

 Huene and others, for all of which proper credit is given. The 

 photographic plates are an especial desideratum, for while it 

 leaves the exact description of the elements somewhat uncertain 

 to the reader, yet one feels more at ease on seeing a photograph 

 of the material. Most of the specimens described are in Walker 

 Museum at the University of Chicago and the American Museum 

 of Natural History in New York City. 



Roy L. Moodie. 



