80 GENEBAL OBNITHOLOGY. 



Aovm for determining what shall be held to be a species, what a conspccies, subspecies, or 

 variety. It is a matter of tact and experience, lilie tlie 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 different li-om the next, that we do not . 

 know or believe to intergrade with that next one ; between which and the next one no inter- 

 mediate equivocal specimens are forthcoming, and none, consequently, are supposed to exist. 

 This is to imply that the differentiatlou is accomplished, the links are lost, and the characters 

 actually become " specific." We treat as " varietal" (jf each other any forms, however differ- 

 ent in their extreme mamfestati(jn, which we know to intergrade, having the intermediate 

 specimens before us, or which we believe with any good reason do intergrade. If the linlcs 

 stiU exist, the differentiation is still incomplete, and the characters are not specific, but only 

 varietal, in the hteral sense of these terms. In the latter case, the oldest name is retained as 

 the specific one, and to it is appended the varietal designation : as, Tiirdus migratorius pro- 

 pinquus. The specific and subspecific names are prefei'ably written with a small initial 

 letter, even when derived from a person or place. 



One other tenii 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 par- 

 entheses; thus, Turdiis (Hylocichla) mustelinus. This is cumbrous, especially when there 

 are already three terms, and is little used in this country. I have latterly discarded it altogether. 

 There is im real difference between a subgenus and a genus, — it is a difference of slight 

 degree merely ; 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 the bird's name tlie name of the original 

 describer of the species, — originally and properly, as the authority or vcaicher for the validity 

 of the species named. But as genera multiplied, it was often found necessary to change the 

 generic name, the species being placed in another genus than tliat to which its original 

 namer refeiTed it. The name of the person who originated the new combmation came to be 

 i^i^cjuerally suffixed, presumably as the authority for the validity of the classification implied. 

 A.s tliis was to ignore the prciprietursliip of the original descril)er, it became eusti unary to 

 retain describer's name in parentheses and add that of the classifier ; thus, Turdus migratorius 

 Liuna3us ; Planesticus migratorius (Linn.) Bonaparte- The pn'actice still prevails; it is im 

 more objectionable than any other hannless exhil:)itiou of human vanity. The student Mill find 

 it carefully carried out in my Check List, and entirely discarded in tlie present work. 



It would take me too far to go fully into the rules of nimieuilature : some few points may 

 be noted. A proper sense of justice to tlie describers of new genera, species, and varieties, 

 prompts us to preserve inviolate the names they see fit to besto\i', \\'itli certain salutary 

 provisions. Hence arises the " law of priority." The ^Vs< name given since 175S is to be 

 retained and used, if it can bo identified with reasonable certitude; that is, if we think we 

 know what the giver meant by it. But it is to be discarded, and the nt'xt uanu' in priority of 

 time substituted, if it is "glaringly false or of express absurdity," — as calling an American bird 

 " africanus" or a black one " alhiis." No generic name can be dupHcated in zoology, and one 

 once void for any reason cannot be revived and used in any connection. The same siiecific 

 name cannot be used twice in the same genus. 



The Actual Classlfleation of Birds has undergone radical modification of lale years, 

 though the same machinery is employed for its expression. This is as would be expected, 

 seeing how profoundly th<! theory of Evcdution has afi'ected our principles of classification, h<i\v 

 completely the morphological has replaced other systems, and how steadily our knowledge ol 

 the structure of birds, and tlieir chron(dogical relations, has progressed. Nevertheless, the 



