XXXll PREFACE. 



under the proposed generic name are usually given, and in some instances 

 characters which really belong to the definition of the genus to which it 

 belongs may be found mingled with them. In these cases it is left for the 

 reader to discover these characters. Should he do so, he becomes the 

 real discoverer of the genus, and as such is entitled to name it. The pub- 

 lication of names in the manner objected to is, from every point of view, 

 pernicious, and is very properlj' forbidden by well-known rules. It mat- 

 ters not if it be ascertained at a subsequent date, and by some circumstan- 

 tial evidence, what the author of such names referred to as to species and 

 specimens. Such information cannot habilitate a nomen nudum ; nor is such 

 circumstantial evidence accessible to students generally, especially to those 

 who live at some distance from the locality whence it may be obtained. 



I now append the most important rules of nomenclature, as adopted by 

 a majority — in most instances, a very large majority — of forty-five of the 

 leading biologists of North America. They are included in the report of a 

 Committee of the American Association for the Advancement of Science, 

 appointed in 1876, of which Capt. W. S. Dall, U. S. N., was chairman.* 



1. The reading of a paper before a scientific body does not constitute a 

 publication of the descriptions or names of animals or plants contained 

 therein. 



2. A name applied to a group of species without a specification of any 

 character possessed by them in connnon (that is, without any so-called 

 generic diagnosis or description), is not entitled to recognition as an estab- 

 lished generic name by subsequent authors. 



3. A generic name applied to a single (then or previously) described 

 species without a generic diagnosis or description of any kind, is not entitled 

 to recognition as above, by subsequent authors. 



4. A subsequent author shall not lie permitted in revising a composite 

 genus (of which no type was specified when it was described) to name as 

 its type a species not included by the original author of the genus in that 

 latter author's list of sj)ecies given when the genus was originall} described. 



5. \Yhen an old genus without a specified type has been subdivided 

 by a subsequent author, and one of the old species is retained and specified 



* See American Naturalist, August, 1678. 



