520 SCIENCE PROGRESS 



in their full development they are regarded by Dr. Case as a 

 mere redundancy of growth, possibly an example of that 

 development of spiny outgrowths and excrescences which ap- 

 pears to mark a decadent group. In addition to North America, 

 pelycosaurs occur in Bohemia (Naosaurus), and not improbably 

 in Central Germany and France; but they appear to be unknown 

 in Russia and Africa. 



Coming to the anomodont, or theromorphous, group, we find 

 Dr. R. Broom, in the journal already quoted (p. 376), describing 

 a new species of the theriodont genus yElnrosaunis from Aliwal 

 North ; while in the Annals of the Natal Museum (vol. i. p. 168) 

 he makes known a new Dicynodon and a new Scymnosaunis 

 from that colon}^ Scyninosmtrus, which is one of the car- 

 nivorous types, appears to be nearly related to Inostranzevia^ 

 of the Russian Permian. In America, Dr. Case has recently 

 described two nearly complete skulls of the cotylosaurian genus 

 Bolosaurus, from the Permian of Texas ; the paper forming 

 article 28 of vol. xxxii. of the Bulletin of the American Museum. 



The relationship of the anomodonts (in the widest sense 

 of that term) to mammals has continued to attract the earnest 

 attention of Dr. Broom, who, in a paper published in the British 

 and South African Association s Repoii for 1907 (vol. iii. p. 12), 

 summarises the evidence in the following words : 



" We may regard it as fairh' well established that mammals 

 are descended from one of the mammal-like reptiles, and almost 

 certainly from a cynodont (theriodont). The known cynodonts 

 are mostly too large to have been the ancestors, but there is 

 evidence of there having been numbers of small forms, and it 

 was probabl}' from one of these that the new stock arose. 

 And I think we ma}^ also safel}^ conclude that all mammals 

 are descended from one common ancestor. By one or two 

 authorities it has been argued that the monotremes are a race 

 apart, and it has even been suggested to remove them from 

 the mammals altogether ; but all recent research has confirmed 

 . the earlier view that monotremes are t^'pical mammals, and in 

 skeletogenesis are quite as near the marsupials as the mar- 

 supials are to the higher forms." 



It may be added that Dr. Broom is firml}- convinced that 

 Tritylodon is a mammal. "As it can be shown," he writes, 

 " from the structure of the molars, that the lower jaw was 

 moved backwards and forwards, as in rodents, it is impossible 



