No. 610] GENETICS VERSUS PALEONTOLOGY 623 



MoUusca . . etc., he is apparently mistaking a part 

 for the whole, and also confusing two fairly distinct lines 

 of investigation, genetics and phylogeny. 



As long as museums and universities send out expe- 

 ditions to bring to light new forms of living and extinct 

 animals and new data illustrating the interrelations of 

 organisms and their environments, as long as anatomists 

 desire a broad comparative basis for human anatomy, as 

 long as even a few students feel a strong curiosity to learn 

 about the course of evolution and the relationships of 

 animals, the old problems of taxonomy, phylogeny and 

 evolution will gradually reassert themselves even in com- 

 petition with brilliant and highly fruitful laboratory 

 studies in cytology, genetics and physiological chemistry. 

 Very likely the fortunate few who gain some first-hand 

 knowledge in all these fields will realize that such prob- 

 lems as the origin of the Mollusca or the origin of the 

 Dicotyledons have as much vitality as the problem of the 

 origin of the earth or the problem of the pliyletic rela- 

 tionship of man with the lower animals. 



The student of the evolution of the vertebrates may well 

 reserve judgment as to theories of evolution, and he must 

 even confess his inability to trace a detailed phylogenetic 

 succession except for short intervals; yet he is well as- 

 sured, from long experience with the paleontological 

 record and with the comparative anatomy of recent ani- 

 mals, that he can trace in a general way the liistory of 

 many groups and of many structures, and he should know 

 very definitely where the evidence is fairly complete and 

 where it is weak and lacking. In view of the wealth and de- 

 tailed character of the evidence (wliich i^ liardly known 

 e\ce])t to a limited nuinher of vjun-iali^t^ ) no competent 

 aiithorilx ^^OlIl(l doiiht, for example, that all the races of 

 ]no(lern H(pmke. walking- on the lip^ <.niicir u„c toed feet, 

 have been derived from three-toed ////y/y^// /^^//-llke t'onn^. 

 or that these in turn lead back to I-lrJn i>/n,s lik<' foi in^ of 

 the Eocene, with' four digits on <'ach for^'foot and tlii'e»» 

 on each liind foot; or that during tiie Tertiary Period the 

 molar teeth of horses (in the broadest sense) changed 



