IS49-] NOMENCLATURE. 371 



reference was given without the author's name being actually 

 appended as part of the binomial name, and I think, except 

 in systematic works, a reference, such as I propose, would 

 damp vanity much. I think a very wrong spirit runs through 

 all Natural History, as if some merit was due to a man for 

 merely naming and defining a species ; I think scarcely any, 

 or none, is due ; if he works out minutely and anatomically 

 any one species, or systematically a whole group, credit is 

 due, but I must think the mere defining a species is nothing, 

 and that no injustice is done him if it be overlooked, though a 

 great inconvenience to Natural History is thus caused. I do 

 not think more credit is due to a man for defining a species, 

 than to a carpenter for making a box. But I am foolish and 

 rabid against species-mongers, or rather against their vanity ; 

 it is useful and necessary work which must be done ; but they 

 act as if they had actually made the species, and it was their 

 own property. 



I use Agassiz's nomenclator ; at least two-thirds of the 

 dates in the Cirripedia are grossly wrong. 



I shall do what I can in fossil Cirripedia, and should be 

 very grateful for specimens ; but I do not believe that species 

 (and hardly genera) can be defined by single valves ; as in 

 every recent species yet examined their forms vary greatly : 

 to describe a species by valves alone, is the same as to 

 describe a crab from small portions of its carapace alone, 

 these portions being highly variable, and not, as in Crustacea, 

 modelled over viscera. I sincerely apologise for the trouble 

 which I have given you, but indeed I will give no more. 



Yours most sincerely, 



C. DARWIN. 



P.S. In conversation I found Owen and Andrew Smith 

 much inclined to throw over the practice of attaching authors' 

 names ; I believe if I agitated I could get a large party to join. 

 W. Thompson agreed some way with me, but was not prepared 

 to go nearly as far as I am. 



VOL. I. 2 C 



