1890 LETTEES TO PEOEESSOE LB CONTE 235 



even apart from this, the work is, to m)- mind, one of 

 the most clearlj- thought out that I have met Anth in 

 Dar-«-inian literature. I have sent it on to ' Nature ' 

 for review, understanding from the office that a copy 

 had not then been received. But for your kind 

 mention of mj^self, I should have reviewed it. 



A most remarkable paper has been sent to the 

 Linnean Society by a Mr. Guhek on ' Divergent 

 Evolution,' for the publication of which in the 

 ' Journal ' you might look out. 



G. J. EOMA^'ES. 

 January 21, 1889. 



My dear Sir, — I should Uke you to set 3'our lucid 

 wits to work upon the following questions, and let me 

 know whether you can devise any answers. 



On pp. 'i'iO-^^G of your book, you state with ex- 

 treme feMcity, and much better than he does, "Weis- 

 mann's theory of the causes of variation. But it does 

 not occm- to him, and does not seem to have occurred 

 to you, that there is a curious and unaccountable 

 interruption in the ascending grades of sexual diffe- 

 rentiation, for in the vegetable kingdom these do not 

 follow the grades of taxonomic ascent ; but, on the 

 contrary, and as a general rule, the lou-o- the order of 

 evolution, the greater is the tendency- to bi-sexuahsm. 

 Dioecious species (i.e. male and female organs on dif- 

 ferent plants) occur in largest proportion among the 

 lower Cryptogams, less frequently among the higher, 

 and more rarelj' still among Phanerogams. Monoe- 

 cious species {i.e. male and female organs on the same 

 plant, but locally distinct) occur chiefly among the 



