6m SCIENCE PROGRESS 



have received much attention during the year. To vol, xxviil 

 pp. 127-239 of the Bull. Amer. Mus. Nat Hist. Dr. R. 

 Broom contributed, for instance, an article on the relation- 

 ship of the Permian reptiles of North America to those of 

 South Africa. After reviewing the leading types of each, he 

 concludes that in the Upper Carboniferous northern South 

 America was the home of a primitive vertebrate fauna 

 from which originated the North American Pelycosauria and 

 the African Anomodontia (in the wider sense of the term). In 

 the Permian this fauna invaded North America, where it soon 

 became isolated. Early in the same epoch the Brazilian genus 

 Mesosaurus reached Africa by a land-bridge, and later on 

 appeared other types, which may have developed in the area 

 now occupied by the South Atlantic. When sundered, the 

 North American and African faunas underwent development 

 in divergent directions, the former displaying many strange 

 specialisations — notably in vertebral spines — while the latter 

 showed a tendency to increase in the size of the limbs. This 

 limb-lengthening, accompanied by the alteration of the phalan- 

 geal formula from 2.3.4.5.4 to 2.3.3.3.3, started the mammalian 

 line of evolution, for directl}^ the more specialised anomodonts 

 raised their bodies above the ground they were well on the 

 way to become mammals. Birds, in fact, adds the author, 

 " are reptiles that became active on their hind limbs ; mammals 

 are reptiles that acquired activity through the development 

 of all four." 



The same subject is continued by Dr. Broom on somewhat 

 different lines in the Trans. R. Soc. S. Africa, vol. i. pp. 473-77, 

 in which the relationship of the American pelycosaurs to the 

 African anomodonts is again emphasised. It is added that 

 during most of the Permian the southern continent was 

 separated by sea from Europe, but that towards the close of 

 this period a land-connection, probably in Asia, was established, 

 by means of which pariasaurians and apparently dicynodonts 

 effected an entrance into Russia. By the Lower Jurassic the 

 European connection had become well established, as the 

 Stormberg dinosaurs are in some cases closely allied to 

 European types, while the African Tritylodon is near akin to 

 the European Triglyphus. 



Intimately connected with the two last is a paper by the 

 same author on the nomenclature of the elements of the amphi- 



