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VARIETAL TERMINOLOGY. 

 By W. F. de Vismes Kane, M.A., F.E.S., &c. 



Mr. Mansbridge's paper on varietal terminology {ante, p. 213) 

 broaches a subject which it would be very desirable to have 

 settled, and the question, being a more or less abstract one, 

 should certainly be capable of easy solution by a consensus of 

 opinion, though its strict application may always offer some 

 difficulty. The standard unit of classification must be the 

 species. And however the definition of a species may be enun- 

 ciated, there seems at least one essential and fundamental 

 element which must enter into it, i. c, the capability to produce 

 fertile progeny. There may of course be exceptions to the rule 

 of hybrids being sterile ; but the law is sufficiently stringent to 

 sup})ly a working basis. Therefore all variations that are 

 capable of producing fertile offspring from a union with the 

 typical specific form are merely subsidiary deviations from the 

 central type. It certainly would be advantageous, if it were 

 possible, to select in every case the central and most universally 

 prevalent form of each species for the type of each group. But 

 the necessities of synonymy require us to maintain the first 

 described form as the type of the species; and this system, 

 though biologically defective, is not beset with much practical 

 inconvenience. \Vhat, then, are the lines we should follow in 

 indicating the various deviations from the type ; that is, a form 

 which represents theoretically a perfect succession of typical 

 characters ? 



In the first place, it is undeniable that each individual of the 

 progeny invariably, so far as we can ascertain, differs in some 

 degree, however small, from the parents. Where the divergence 

 is sufficiently appreciable to make it convenient to ear-mark it, 

 it may be well to name it and class it as an "aberration," — a 

 term wide enough to include every (no matter how narrow or 

 wide) branching from the main stem. The greatest part, however, 

 of such aberrant forms disappear as they arise, mainly through 

 the action of extensive interbreeding, and so these eccentricities 

 become neutralised by the operation of the law of heredity. But 

 when isolation becomes a factor, and compels in-and-in breeding 

 among such aberrations ; or some similar determinant interferes, 

 such as the principle of the "survival of the fittest"; the aberra- 

 tional characteristic becomes fixed and inherited in a more or 

 less degree ; thus giving rise to a permanent " variety." As in a 

 kaleidoscope, there are patterns rapidly succeeding each other, 

 and disappearing never to return except after the lapse of long 

 periods; while others, from the nature of the materials, reappear 

 more or less identically at frequent intervals, offering salient cha- 

 racteristics worth notice. And similarly with the shifting factors 



