68 EVOLUTION [CHAP. II 



code of rules for Zoological Nomenclature, now known by his name 

 the principles of which are very generally accepted." Mr. Darwin's 

 reasons against appending the describer's name to that of the species 

 are given in Life and Letters, p. 366. The present letter is of interest 

 as giving additional details in regard to Darwin's difficulties. 



Letter 30 Down, Feb. loth [1849]. 



I have again to thank you cordially for your letter. Your 

 remarks shall fructify to some extent, and I will try to be 

 more faithful to rigid virtue and priority ; but as for calling 

 Balanus "Lepas" (which I did not think of) I cannot do it, 

 my pen won't write it it is impossible. I have great hopes 

 some of my difficulties will disappear, owing to wrong dates 

 in Agassiz and to my having to run several genera into one ; 

 for I have as yet gone, in but few cases, to original sources. 

 With respect to adopting my own notions in my Cirripedia 

 book, I should not like to do so without I found others 

 approved, and in some public way ; nor indeed is it well 

 adapted, as I can never recognise a species without I have 

 the original specimen, which fortunately I have in many cases 

 in the British Museum. Thus far I mean to adopt my notion, 

 in never putting mi/ti or Darwin after my own species, and in 

 the anatomical text giving no authors' names at all, as 

 the systematic part will serve for those who want to know 

 the history of the species as far as I can imperfectly work 

 it out. 



I have had a note from W. Thompson x this morning, and 

 he tells me Ogleby has some scheme identical almost with mine. 

 I feel pretty sure there is a growing general aversion to the 

 appendage of author's name, except in cases where necessary. 

 Now at this moment I have seen specimens ticketed with a 

 specific name and no reference such are hopelessly incon- 

 venient ; but I declare I would rather (as saving time) have a 

 reference to some second systematic work than to the original 

 author, for I have cases of this which hardly help me at all, 

 for I know not where to look amongst endless periodical 

 foreign papers. On the other hand, one can get hold of most 

 systematic works and so follow up the scent, and a species 

 does not long lie buried exclusively in a paper. 



1 Mr. Thompson is described in the preface to the Lepadidce as " the 

 distinguished Natural Historian of Ireland." 



