1896.] The Formulation <>f the Xa turn I Sciences. 105 



rest on characters, we must continue to depend on their indi- 

 cations, no matter whether the result gives us phyletic series 

 or not. In the next place, we must remember that we have in 

 every country interruptions in the sequence of the geological 

 formations, which will give us structural breaks until they are 

 filled. There are also periods when organic remains were not 

 preserved ; these also will give us interruptions in our series. 

 So we shall have to adhere to our customary method without 

 regard to theory, and if the phyletic idea is correct, as I believe 

 it to be, it will appear in the final result, and at some future 



Authors are frequently careless in their definitions. Aery 

 often they include, in the definition of the order, characters 

 which belong in that of the family, and in that of the family 

 those that belong in the genus. Characters of different values 

 are thus mixed. The tendency, especially with naturalists 

 who have only studied limited groups, is to overestimate the 

 importance of characters. Thus the tendency is to propose 

 too many genera and other divisions of the higher grades. In 

 some groups structure has been lost sight of altogether, and 

 color patterns, dimensions, and even geographical range, 

 treated as characters of genera. As the mass of knowledge in- 

 creases, however, the necessity for precision will become so 

 pressing that this kind of formulation will be discarded, and 

 definitions which mean something will be employed. Search 

 will be made especially for that one character which the nature 

 of the series renders it probable will survive, as discoveries of in- 

 termediate forms are successively made, and here the tact and 

 precision of the taxonomist has the opportunity for exercise. 

 In the selection of these characters, one problem will occasion- 

 ally present itself. The sexes of the same species sometimes 

 display great disparity of developmental status, sometimes the 

 male, but more frequently the female, remaining in a rela- 

 tively immature stage, or in others presenting an extraordi- 

 nary degeneracy. In these cases the sex that displays what 

 one might call the genius, or in other words, the tendency, 

 of the entire group, will furnish the definitions. This will 

 generally be that one which displays the most numerous char- 



