282 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



member of this perfect series of forms has been specially- 

 created; and if it can be proved, as the facts certainly do 

 prove, that a complicated animal like the horse may have 

 arisen by gradual modification of a lower and less specialized 

 form, there is surely no reason to think that other animals 

 have arisen in a dift'erent way. This case, moreover, is not 

 isolated. Every new investigation into the Tertiary mam- 

 malian fauna brings fresh evidence, tending to show how the 

 rhinoceros, the pigs, the ruminants, have come about. Sim- 

 ilar light is being thrown on the origin of the carnivora, and 

 also, in a less degree, on that of all the other groups of ani- 

 mals. It is not, however, to be expected that there should 

 be, as yet, an answer to every difficulty, for we are only just 

 beginning the study of biological facts from the evolution- 

 ary point of view. Still, w^hen we look back twenty years 

 to the publication of the ' Origin of Species,' we are tilled 

 with astonishment at the progress of our knowledge, and 

 especially at the immense strides it has made in the region 

 of paleontological research. The accurate information ob- 

 tained in this department of science has put the fact of evo- 

 lution beyond a doubt ; formerly the great reproach to the 

 theory was that no support was lent to it by the geological 

 history of living things ; now, whatever happens, the fact 

 remains that the hypothesis is founded on the firm basis of 

 paleontological evidence." 



PROFESSOK marsh's PALEOXTOLOGICAL DISCOVERIES. 



Professor O. C. Marsh, in a lecture to the graduating class 

 of Yale College, summed up the main results of his paleon- 

 tological researches in the Rocky Mountains. A syllabus 

 of the lecture is published in the America?i Journal of Sci- 

 ence. His conclusions as to the size and growth of the brain 

 in mammals, from the beginning of the Tertiary to the pres- 

 ent time, may be briefly stated thus: 1. All tertiary mam- 

 mals had small brains. 2. There was a gradual increase in 

 the size of the brain during this period. 3. This increase 

 was mainly confined to the cerebral hemispheres. 4. In 

 some groups the convolutions of the brain have gradually 

 become more complicated. 5. In some the cerebellum and 

 olfactory lobes have even diminished in size. There is some 

 evidence that the same law of brain-growth holds good 



