PRINCIPLES AND PRACTICE OF CLASSIFICATION. 79 



to intergrade ; aud the original edition of my Check List (1873) distinguished such by the sign 

 " var." intervening between the specific and the subspecific name. I subsequently determined 

 to do away with the superfluous term " var.," and in the next edition of the Check List (1882) 

 and Key (1884) adopted a purely trinomial system of naming the equivocal forms as subspecies; 

 as, Loxia curvirostra americana. This method was found to work so well, that it was immedi- 

 ately adopted and officially formulated in the Code of Nomenclature (188fi) of the American 

 Ornithologists' Union, and thus came into universal use in this country. Trinomialism is con- 

 fidently commended as a boon to our brethren over the sea, who perceive its usefulness, yet 

 continue to handle it gingerly, Linnaaus being still something of a fetich on the more conserva- 

 tive side of the water. It is the most distinctive feature of what English ornithologists call 

 "the American school." 



The Student cannot be too well assured, that no such things as species, in the old 

 sense of the word, exist in nature, any more than have genera or families an actual existence- 

 Indeed they cannot be, if there is any truth in the principles discussed in our earlier paragraphs. 

 Species are simply ulterior modifications, which once were, if they be not still, inseparably 

 linked together; and their nominal recognition is a pure convention, like that of a genus. 

 More practically hinges upon the way we regard them than turns upon our establishment of 

 higher grtmps, simply because upon the way we decide in this case depends the scientific labeling 

 of specimens. If we are speaking of a Robin, we do not ordinarily concern ourselves with the 

 fiiuiily or order it belongs to, but we do require a technical name for constant use. That name 

 is compounded of its genus, species, and variety. No infallible rule can be laid down for deter- 

 mining what shall be held to be a species, what a conspecies, subspecies, or variety. It is a 

 matter of tact and experience, like appreciation of the value of any other group in zoology. 

 There is, however, a convention upon the subject, which the present workers in ornithology in 

 this country find available; at any rate, we have no better rule to go by. We treat as 

 " specific" any form, however little difi'erent from the next, that we do not know or believe to 

 intergrade with that next one — between which and the next one no intermediate equivocal 

 specimens are forthcoming, and none, consequently, are supposed to exist. This is to imply 

 that the difierentiation is accomplished, the links are lost, and the characters actually become 

 "specific." We treat as "subspecific" of each other any forms, however different in their ex- 

 treme manifestation, which we know to intergrade, having the intermediate specimens before 

 us, or which we believe with any good reason do intergrade. If the links still exist, the differ- 

 entiation is still incomplete, and the characters are not specific, but only subspecific, in the 

 literal sense of these terms. In the latter case, the oldest approved name is retained as the 

 specific one, and to it is appended the subspecific designation : as Merula migratoria propinqua. 

 The specific and subspecific names are preferably written with a small initial letter, even when 

 derived from the name of a person or place. 



One other term than those just considered sometimes forms part of a bird's scientific name: 

 this is the subgenus. When introduced, it always follows the generic term, in parentheses; 

 thus, Turdus (Hglocichla) mustelinus. This is cumbrous, especially when there are already 

 three terms, and is Httle used in this country. I discarded it altogether in 1884. and so did the 

 American Ornithologists' Union in 1886. There is no real difiierence between a subgenus and 

 a genus, and modern genera have so multiplied that one can easily find a single name for any 

 generic refinement he may wish to indulge. 



It has always been customary to write after a bird's name the name of the original describer 

 of the species, as the authority or voucher for the validity of the species named. But as genera 

 nmltiplied, it was often found necessary to change the generic name, the species being placed 

 in another genus than that to which its original namer had referred it. Then the name of the 

 person who originated the new combination was commonly suffixed, presumably as authority 



