TYPE AMMONITES— VI Feb. 



definite as to one example. Whatever be the species of that one example 

 is then always the genotype species, while the one example always 

 remains the genotype standard of reference. 



The foregoing was submitted to Dr. Bather, who very kindly sent 

 the following remarks, which he has given me permission to publish : 



On Genotypes, by Dr. F. A. Bather. As C. Schuchert says, in 

 his introduction to the Catalogue of Type specimens of Fossils in the 

 U.S. National Museum, a genotype is a species, not a specimen. To this 

 statement " strictly speaking " you agree. 



This being admitted, certain difficulties may arise, as you have 

 foreseen, and as is matter of frequent experience. They are generally 

 due to a misreading of the genotype through failure to study its holotype. 

 The way you have chosen to prevent those difficulties is, in my opinion, 

 illogical. On such matters I am constantly consulted, and the following 

 is the advice which I invariably give. 



In establishing a new genus an author should fix on one species 

 as the genotype (or genoholotype) . The standard of that genotype is 

 the holotype of the species. Therefore, if there be no holotype, it is 

 his business to select one (lectotype). If possible, he should become 

 personally acquainted with the syntypes, so that he will select an 

 appropriate specimen. In any case, it is to be presumed that he does 

 not venture to make any species the type of a new genus, unless he is 

 familiar with its holotype, since it is by that specimen in the last resort 

 that the genus must be judged. The holotype of the geno- 

 type is the ultimate standard of reference. 



Now, if the author is prevented by inevitable circumstance or by 

 laziness from doing this work, and if he has to leave others to do it for 

 him — that is to say, if he thinks himself obliged to make a new genus 

 without knowledge of its type-species, because such a course is suggested 

 by a specimen or specimens that he refers to that species, then the follow- 

 ing is the course of action to follow. He should select one of those 

 specimens and say : " If it be found that the genotype or type-species 

 is not what I imagine it to be, i.e., is not conspecific with the specimen 

 before me, then it is to be understood that my new genus is to be 

 interpreted by this specimen, which will be the holotype of, or will fall 

 into, a new species, and that species will be the genotype of my genus." 



The preceding, you will see, has in the end the same practical result 

 as your action, but is not open to the same criticism. It is, in my 

 opinion, preferable because it does not encourage slovenly work, but 

 urges on the author the need, for studying the actual type-material. 



I can see no radical difference between Dr. Bather's use of the word 

 genotype and mine, except this : that I use the word I' genotype " quite 

 short where it should be said ' the one standard of reference for the 

 genotype species.' We are both agreed that it comes down ultimately 

 to one specimen. But Dr. Bather has started another hare altogether — 

 that is, the method to be used in choosing a genolectotype out of various 

 examples of a species. He says, in effect, that if an author writes Ab, 

 wherein A is a new generic name, then the holotype of b automatically 

 becomes the genotype standard of reference for the generic name A. 

 I dissent. I say that if Ab represents a multitude of species, as it 

 really did in uncritical days, then all the species of these forms which 

 are known as b prior to the giving of the name A are really genosyntypes, 



