NEOLAMARCKISM 403 



Ryder began in 1877 to publish a series of remark- 

 ably suggestive essays on the" mechanical genesis," 

 through strains, of the vertebrate limbs and teeth, 

 including the causes of the reduction of digits. In 

 discussing the origin of the great development of 

 the incisor teeth of rodents, he suggested that " the 

 more severe strains to which they were subjected by 

 enforced or intelligently assumed changes of habit, 

 were the initiatory agents in causing them to assume 

 their present forms, such forms as were best adapted 

 to resist the greatest strains without breaking." * 



He afterwards t claimed that the articulations of 

 the cartilaginous fin-rays of the trout (Salmo fonti- 

 nalis) are due to the mechanical strains experienced 

 by the rays in use as motors of the body of the fish 

 in the water. 



In the line of inquiry opened up by Cope and by 

 Ryder are the essays of Osborn:j: on the mechanical 

 causes for the displacement of the elements of the 

 feet in the mammals, and the phylogeny of the 

 teeth. Also Professor W. B. Scott thus expresses 

 the results of his studies : § 



" To sum up the results of our examination of cer- 

 tain series of fossil mammals, one sees clearly that 

 transformation, whether in the way of the addition 

 of new parts or the reduction of those already pres- 

 ent, acts just as if the direct action of the environ- 



* Proceedings Academy of Natural Science, Philadelphia (1877), 

 p. 318. 



f Proceedings of the American Philosophical Society (1889), p. 546. 



X Transactions American Philosophical Society, xvi. (1890), and 

 later papers. 



% American Journal of Morphology (1891), pp. 395, 398. 



