Notes on Nomenclature. 93 



find out from it what are the characters which are connoted 

 by tliat name. 



That in which Thorell in Europ. Spid. and Simon in Hist. 

 Nat. Ar. have made so excellent a beginning by selecting 

 types for genera has to be continued, taking care that all 

 types are fixed by one and the same definite process, so that 

 errors in the various steps can be corrected, and the whole 

 science placed upon some solid and definite basis. 



The Selected Type. 



When we have made up our minds that type-species are 

 a necessity in systematic zoology, we shall be in a position 

 to discuss the processes of arriving at this type. 



Dr. Dahl quotes three points in which he supposes that 

 the rules I follow dififer from those of the International Con- 

 gress. The third is this : '^ Any author^ even some time after 

 the establishment of a genus, may fix the type, if the first author 

 has omitted to do so.''^ Dahl adds that 1 seem to assume that 

 the International RiiJes would be against the process of elimi- 

 nation for the estr^,blishment of a definite type. On the 

 contrary, it would never occur to me that any body of rules 

 should contemplate an attitude so illogical, in view of their 

 decision in paragraph 35, that the first author has to ascribe 

 the original name of the genus to that part of it which 

 he considers suitable. 



By what right do these rules tamper with the original 

 genus at all? Limited in any way, the result cannot be said 

 to be the original author's conception of his genus. And if 

 the exigencies of systematic zoology demand a further limi- 

 tation to a single species, even an International Congress 

 cannot dispute the right to take that action. But if the 

 International Rules still adhere to the decision that the deter- 

 mination of the author who first breaks up the genus 

 " cannot afterwards be modified^'' then no type-species can 

 ever be fixed upon in cases where more than one species has 

 been left in by the first author's action. 



As to the absence of a paragraph on the pointj this simply 

 means that the necessity of fixing on a single type-species 

 never occurred to those who drew up the rules. 



I have, however, never heard any reasonable argument 

 against regarding tlie first definitely selected type-species as 

 " the type'''' to which all may refer when they wish to know 

 what tlie characters of a genus may be. One might object 

 that a species possibly would be selected which afterwards 

 Ann. & Mag. N. Hist. !Ser. 7. Vol. x. S 



