900 



SCIENCE 



[N. S. Vol. XLI. No. 1068 



confusion which has not received adequate at- 

 tention. Apparently it is regarded as quite 

 unavoidable, or perhaps it is not commonly 

 thought of as a diiBeulty of nomenclature 

 at all. I refer to the continual changing of 

 names that results from the subdivision of 

 genera. Who has not experienced the peculiar 

 feeling of mingled dismay and exasperation 

 which follows the discovery that some long- 

 familiar genus, whose species are to most of us 

 scarcely distinguishable as species, has been 

 split over night into a half dozen new genera? 

 In place of the familiar collective group — 

 Jonesia, let us say — we now have Neojonesia, 

 Eujonesia, Pseudojonesia, Megajonesia, Micro- 

 jonesia and Hetero jonesia, or perhaps a set of 

 names that no longer even suggest the former 

 i:nit. And if we look for the distinctions 

 upon which these subdivisions are based, we 

 commonly find that the differences are very 

 trifling indeed in comparison with the many 

 and detailed points of resemblance between 

 these various groups. 



Let me not be misunderstood. Difl^erences, 

 however slight, ought when constant to be 

 recognized and in some way incorporated into 

 the tasonomic structure. " Splitting," so far 

 as it is based upon the detection of such dif- 

 ferences, is a legitimate and indeed inevitable 

 process, if systematic zoology is to progress. 

 Why, then, should one object to the indefinite 

 subdividing of genera? And is it not highly 

 presumptuous for one who is not a taxonomist 

 at all to be offering his opinions as to what 

 constitutes a difference of generic value? 



Taking up the first of these questions, it 

 must be borne in mind that in the Linnaean 

 system of binomial nomenclature the generic 

 name plays two quite distinct roles. One of 

 these is to designate a taxonomic group, sup- 

 posed to be intermediate between the family 

 and the species. The other is to form the first 

 half of the " scientific " namte of each species 

 within that group. It is for this reason that 

 the changing of a generic name is so much 

 more disconcerting than is changing that of 

 a family or order. And this is why, in the 

 writer's opinion, such splitting as we have just 

 recognized to be inevitable should be done 



within the limits of the genus, either by the 

 creation of " subgenera," or, if necessary, by 

 the establishment of wholly new categories be- 

 tween the genus and the species. 



As regards the second point above raised, 

 I should indeed feel much diffidence in 

 offering my opinion on this subject were 

 there even an approach to unanimity in re- 

 spect to what constitutes a character of generic 

 value. It is frequently said that the genera 

 of Linnseus are the families of to-day, while 

 it is doubtless also true that some LinnEean 

 species constitute present-day genera. Even 

 now, the inclusiveness of the concept genus 

 varies enormously in different groups of or- 

 ganisms. In general, those groups which 

 have been studied most intensively by syste- 

 matists are doubtless on the whole those in 

 which the concept has acquired the most re- 

 stricted meaning. This narrowing down of 

 the inclusiveness of the genus is thus an evil 

 which may seem to be progressive and incur- 

 able. Its logical outcome is the erection of a 

 separate genus for each species, in which event 

 the two categories will become identical. 

 When that has come to pass, no further 

 changes of nomenclature will be possible, and 

 we shall have attained the much-desired sta- 

 bility. At the same time, all verbal clues to 

 the nearer kinships between species will have 

 been lost, and biology will be to that extent 

 poorer. 



Taxonomists are too prone to regard this 

 whole question of nomenclature as one which 

 is exclusively their own. The intrusion of an 

 outsider into the fray is likely to be hotly re- 

 sented. I remember venturing, several year? 

 ago, to express some of the above views in a 

 letter to a well-known authority on one of the 

 larger groups of invertebrate animals. No 

 reply whatever was made to the line of rea- 

 soning set forth by me. I was merely 

 " squelched " with the rejoinder that if I had 

 sufficiently wide experience in describing spe- 

 cies I would see things in a different light — a 

 statement which is possibly true, though pro- 

 ving nothing as to the point at issue. Our 

 taxonomic brethren have so long been treated 



