408 MISCELLANEA. [1876. 



essays by which the author has done such admirable service 

 to the cause of evolution :] 



C. Darwin to Aug. Weismmin. 



January 12, 1877. 



... I read German so slowly, and have had lately to read 

 several other papers, so that I have as yet finished only half 

 of your first essay and two-thirds of your second. They 

 have excited my interest and admiration in the highest de- 

 gree, and whichever I think of last, seems to me the most 

 valuable. I never expected to see the coloured marks on 

 caterpillars so well explained ; and the case of the ocelli de- 

 lights me especially. . . . 



. . . There is one other subject which has always seemed 

 to me more difficult to explain than even the colours of cater- 

 pillars, and that is the colour of birds' eggs, and I wish you 

 would take this up. 



C. Darwin to Melchior Neiimayr^^ Vienna. 



Down, Beckenham, Kent, March 9, 1877. 



Dear Sir, — From having been obliged to read other 

 books, I finished only yesterday your essay on * Die Conge- 

 rien,' &c.f 



I hope that you will allow me to express my gratitude for 

 the pleasure and instruction which I have derived from read- 

 ing it. It seems to me to be an admirable work ; and is by 

 far the best case which I have ever met with, showing the 

 direct influence of the conditions of life on the organization. 



Mr. Hyatt, who has been studying the Hilgendorf case, 

 writes to me with respect to the conclusions at which he has 

 arrived, and these are nearly the same as yours. He insists 

 that closely similar forms may be derived from distinct lines 

 of descent ; and this is what I formerly called analogical 

 variation. There can now be no doubt that species may be- 

 come greatly modified through the direct action of the envi- 



* Professor of Palaeontology at Vienna. 



f ' Die Congerien und Paludinenschichten Slavonians,' 4to, 1875. 



