Terminology 



Dr. F. A. Bather, F.R.S., of the British Museum (Nat. History) 

 writes : " I have been reading [Type Amm., Vol. V] with deep interest. 

 But I wish you would make it clearer that a genotype or lectogenotype 

 is a species, not a specimen. I really think that this is of some 

 importance. There are passages and especially legends to plates which 

 tend to confusion." 



Strictly speaking. Dr. Bather is perfectly correct — the genotype 

 is a species ; but as there always can be differences of opinion as to 

 whether certain specimens belong to a species or should be separated, 

 the actual specimen to which the generic name was first applied becomes, 

 when it is positively known as such specimen, the only example about 

 whose identity there can be no dispute. Such original specimen is thus 

 the actual type of reference for determining the characters of the genus. 

 So I have always quite deliberately pinned the genotype species down 

 to the basis of one original specimen. When authors have given a 

 generic name to species without definite fixing on one, I have chosen 

 first one species and then one specimen — a lectogenotype, as Dr. Bather 

 writes, or a genolectotype, as I have written, to be the one definite 

 standard. Thus for the genotype or the genolectotype species there is 

 one and only one actual standard of reference. I have used the term 

 genotype for short instead of writing ' the ultimate standard of refer- 

 ence whereon the genotype species rests, and by which it has to be 

 determined.' 



The generic name does not follow the cited species, it follows the 

 cited standard specimen : it is the identity of the standard specimen 

 which rules the genotype species, not the name of the cited species 

 which rules the identity of the genotype standard. Oftentimes the 

 attributing of the genotype standard to a given species may be incorrect. 



For example, I have given the generic name Gigantites to a specimen 

 supposed to be conspecific with Sowerby's Ammonites giganteus (T.A. 

 Ill, CCLVI). This identity may be wrong. If so, the generic name 

 Gigantites remains fixed on my giganteus, whatever that may be ; it does 

 not pass over to Sowerby's Ammonite's giganteus, however often the 

 genotype species of Gigantites may have been cited as being Gigantites 

 giganteus, J. Sowerby sp. I have protected my specimen by definitely 

 placing the word ' Genotype ' in its legend. But, had I not done so, 

 I hold that it should be taken as the ' genotype standard of reference.' 



It is, therefore, in my opinion, imperative that in giving a new 

 generic name, the author should not merely cite a given species by name, 

 but should cite one definite specimen of that species for the type of 

 his genus ; because the species which he selects may contain many 

 specimens : in his opinion these may be conspecific, but it does not 

 follow that future observers will agree in that view. Then there is 

 trouble as to which form is to be selected : all this is avoided by being 



