SEC. II PRINCIPLES AND PRACTICE OF CLASSIFICATION 121 



binomially with those lesser groups than species, commonly called 

 " varieties," now better designated as " conspecies " or " subspecies '' ; 

 and he often used a third word, separated however from the binomial 

 name by intervention of the sign "var." or some other symbol. 

 Thus, if he had supposed an American crossbill to be a variety of a 

 European Loxla leucojjtera, he might have called it Loxia leucoptera, a, 

 americana. Some years ago, in treating of this subject, I urged the 

 necessity of recognising by name a great number of forms of our 

 birds intermediate between nominal species, and connecting the 

 latter by links so perfect, that our handling of species required 

 thorough reconsideration. The dilemma arose, through our very 

 intimate knowledge of the climatic and geographical variation of 

 species, either to discard a great numljer that had been described, 

 and so ignore all the ultimate modifications of our bird-forms ; or else 

 to recognise as good species the same large number of forms that we 

 knew shaded into each so completely that no specific character could 

 be assigned. In the original edition of the Key to North Anierican 

 Birds (1872), I compromised the matter by reducing to the rank of 

 varieties the nominal species that were known or believed to inter- 

 grade ; and 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 Avith the 

 superfluous term "var.," and in the next edition of the Check List 

 (1882) reverted to a purely trinomial system of naming the equi- 

 vocal forms ; as, Loxia curvirostra americana. This system is found 

 to work well, and seems likely to come into general use.^ 



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 groups, simply because upon the 

 way we decide in this case depends the scientific labelUn/j of specimens. 

 If we are speaking of a robin, we do not ordinarily concern our- 

 selves with the family or order it belongs to, but we do require a 



^ Since the above was penned, the trinominal or trionyniic system of nomeucLature 

 has been formulated and fully adopted by the conmiittee on Nomenclature of 

 the American Ornithologists' Union, of which Dr. Cones was chairman ; and the 

 decision of that body of uomenclatural legislators, as expressed in its Canons of 

 Nom.enclature, has been recognised as authoritative not only by American ornitholo- 

 gists in general, but by naturalists in other departments of zoology, notably mam- 

 malogy, herpetology, ichthyology, malacology, anil entomology. The scheme has 

 become well known to British ornithologists as a distinctive feature of the "American 

 School." 



