174 NEW YORK STATE MUSEUM 



them as an increment to zoological science, compacting its substantial 

 framework and vastly extending our knowledge of the evolutionary history 

 of organisms. Are we proposing to ourselves an explanation of life, our 

 vision must include not only living matter as we find it today, but 

 also those manifestations of it that existed in the remote past. Side by 

 side with the development of the individual we must examine the evolu- 

 tionary history of the race. The more we learn of vital processes now 

 operating, the better able are we to understand their operation in times 

 anterior to our own. Comparisons that are enlightening when made 

 between members of the modern fauna may often be profitably extended 

 so as to include members of extinct faunas. Where the time element acts 

 as an impediment to our studies it must be eliminated so far as possible. 

 Zoology of the past does not differ in essence from zoology of the present, 

 any more than ancient history differs fundamentally from modern. 



Among other large problems that suggest themselves in reviewing our 

 knowledge of Devonic fishes are those relating to the habits and mode of 

 life of the creatures represented, their adaptation to physical environment, 

 the effects of such adaptation as manifested in their structural modifications 

 and subsequent racial history, and finally the important topics of migration 

 and geographical distribution. All of these issues, though subsidiary to the 

 main theme, offer nevertheless fruitful fields for exploration. It would 

 take us too far astray from the immediate purpose of this paper to consider 

 all of these matters seriatim, particularly as materials are already at hand 

 for those who may wish to pursue them further. For instance, in regard 

 to the habits and mode of existence of ancient forms of fish life, many sug- 

 gestive hints are contained in the writings of Claypole,' Dollo,^ Jaekel,^ 

 Kemna"* and others. 



' Several papers in the American Geologist, particularly his posthumous one con- 

 tained in volume 32 (1903), under the title, Tlie Devonian Era iti the Ohio Basin. 



^Recent papers in Bulletin de la Societe Beige de Geologie, etc. 



3Neue AVirbeltierfunde aus dem Devon von Wildungen. Sitzungsber. Gesellsch. 

 naturforsch. Freunde, no. 3, Jahrg. 1906. 



■•Les recentes decouvertes de poissons fossiles primitifs. Bui. Soc. Beige. 1904. 18: 

 65-78. 



