774 



SCIENCE. 



[N. S. Vol. XXIV. No. 624. 



be * correctly inferred ' that the first species 

 was regarded by the author as the type of his 

 genus, provided that it proved ' accurately to 

 agree' with the definition of the genus. At 

 the same time, the principle of tautonomy, 

 only recently formally adopted, and only by a 

 few authors,^ was foreshadowed as an impor- 

 tant aid in determining types, and whenever 

 in this way a certain species was distinguished 

 from the others, the B. A, Committee ruled 

 that this particular species * must be regarded 

 as the original type of a genus,' and in case 

 some other species had been taken as the type, 

 * we are justified in restoring the name of the 

 old genus to its typical signification, even 

 when later authors have done otherwise.' It 

 was recognized also that by invariably taking 

 the first species as type, the author's real in- 

 tention in establishing a genus might be an- 

 nulled. While some authors are known to 

 have placed their typical species first on the 

 list, it is known that others gave it a central 

 position. 



The method of determining generic types, 

 abroad as well as in America, has not been 

 uniform, but has often been done loosely and 

 without rigid system of any sort: and hence 

 the present confusion. While some authors 

 may have consistently followed the first spe- 

 cies principle, and other may have done so 

 occasionally to tide over an emergency, the 

 first species rule has never been incorporated 

 into any code of zoological nomenclature, 

 while the elimination principle has ever been 

 a basic principle in all — not in express terms, 

 but as an inevitable result of the rules for 

 determining types. Consequently, the large 

 number of originally composite genera having 

 the first species as type, shown by Mr. Stone's 

 statistics, is the result of coincidence rather 

 than the conscious application of a 'first spe- 

 cies ' principle. 



It has been claimed that a large number of 

 ' minute rules ' are necessary for the applica- 

 tion of the principle of elimination, a point 

 emphasized by Mr. Stone in his reference to 

 Dr. Stiles's method, which is by no means so 

 complicated and abstruse as Mr. Stone's pass- 



''See Science, N. S., Vol. XVI., pp. 114, 115, 

 July 18, 1902. 



ing reference to it would imply. As I have 

 said in another connection: 



The method of fixing generic types by elimina- 

 tion is merely the process of applying the rule 

 of priority to genera formed by the breaking up 

 of comprehensive groups originally designated as 

 genera. It has been objected to as abstruse and 

 difficult of application, even by some who have, 

 but unconsciously, been in the habit of using 

 it. * * * 



(a) An author who first subdivides a genus 

 may restrict the original name to such part of it 

 as he may judge advisable, and such assignment 

 shall not be subject to subsequent modification 

 (=A. O. U. Code, Canon XXI.). 



(6) When, however, any of the original species 

 of a genus have been removed by subsequent au- 

 thors, and have become types of, or are strictly 

 congeneric with the types of, other genera, with- 

 out the designation of any of them as the type of 

 the original genus, the type must be chosen from 

 the remaining species; if, however, all have been 

 removed, the last species thus removed shall be 

 taken as the type of the original genus. If, how- 

 ever, the genus originally contained both exotic 

 and non-exotic species — from the standpoint of the 

 author — and the generic term is one originally ap- 

 plied by the ancient Greeks or Eomans, the last 

 of the non-exotic species to be removed shall be 

 taken as the type of the original genus. 



This is the elimination method — simple and 

 perfectly easy of comprehension, but liable to 

 give rise to perplexing complications through 

 questions of synonymy, arising from the fact 

 that certain groups that have been separated 

 and named as generic are treated by some 

 authors as genera and by others relegated to 

 synonymy. It necessitates, however, a thor- 

 ough knowledge of the literature of the cases 

 involved, and of the zoological relationships 

 of all the species concerned in the inquiry. 

 It is, therefore, not a task a novice should 

 meddle with; but there is no prohibitory law 

 against incompetents, to whose meddling in 

 the past our present state of uncertainty in 

 not a few cases is due. 



On the other hand, according to Mr. Stone's 

 presentation of the case, it is perfectly easy 

 for anybody able to read to determine the type 

 of a genus. He says: "It is necessary to 

 consult only the original reference to ascer- 

 tain the type of the genus." " The question 



