84 Scientific Intelligence. 



animals as affected by climate and evolution" or "The theory of 

 land bridges as negated by climate and evolution." As is well 

 known, the author is an ai-dent believer in the permanency of 

 continents and ocean basins as they now exist, though the study 

 in hand aims to prove the hypothesis for Cenozoic time only. 

 However he states that "If the distribution of animals be inter- 

 preted along the lines here advocated, there is no occasion for a 

 Gondwana Land even in the Paleozoic" (191). The reviewer 

 thinks his conclusion sound when restricted to the Cenozoic, but 

 to say there was no Gondwana in early Mesozoic time, and 

 especially none in Permian time, is to drag into this painstaking 

 and most excellent study an unnecessary and unproved conclu- 

 sion. 



The work is replete with facts and new ideas regarding the 

 dispersal of animals (mainly mammals), interpreted on the basis 

 of periodic changes of climate from moist, uniform, and warm to 

 arid, to zonal, and glacial ones. The writer seeks to prove that 

 the present distribution of life in the various continents can be 

 best explained by radial dispersal from Holarctic centers with 

 variable climates (Europe, Asia, North America) into the periph- 

 eral lands (South America, Africa, Australasia). His main prin- 

 ciple of dispersal is that in the evolution of a race "it should be 

 at first most progressive at its point of original dispersal, and it 

 will continue this progress at that point in response to whatever 

 stimulus originally caused it and spread out in successive waves 

 of migration, each wave a stage higher than the previous one. 

 At any one time, therefore, the most advanced stages should be 

 nearest the center of dispersal, the most conservative stages far- 

 thest from it. It is not in Australia that we should look for the 

 ancestry of man, but in Asia" (180). Finally our knowledge of 

 fossil land animals is almost wholly of those of the lowlands, 

 with but rare glimpses of an upland form (274). 



As the oceanic islands have life derived from the adjacent 

 continents, the author explains the arrival of this life over sea as 

 due to natural rafts. He argues that for every raft seen a 

 hundred have probably drifted out unseen, and if Ave concede 

 that 1000 have probably occurredin three centuries, then 10,000,000 

 (by an error he states 30,000,000) would have occurred in the 

 Cenozoic. He further estimates that only 1,000,000 will have 

 living animals upon them, of these only 10,000 will reach land, 

 and in only 100 of these cases will the species establish a foothold. 

 This is quite sufficient to cover the dozen or two of Mammalia on 

 the larger oceanic islands " (206-207). Undoubtedly there is 

 some truth in these figures, especially for very small animals, but 

 such rafts can hardly have been a marked factor in the dispersal 

 of land animals. 



Doctor Matthew does not believe in the fracturing of continents 

 as evidenced by the separation of Madagascar from Africa, nor 

 does he hold to the idea that where mountains are now seen to 

 terminate abruptly facing the ocean (as in the Maritime Provinces 



