MEMOIR. Iv 
selection may have come into play here. For when ducks were first tamed, 
strong flyers would less readily submit than weak ones, and so forth. 
‘‘The general blindness of animals in deep caverns seems to be partly 
owing to direct effect of external condition on individuals, leading to disuse 
of the organs, and collapse of muscles and nerves, reproduced in offspring. 
‘But this belongs to the same class of facts as those cases which show 
a general similarity, in some features, amongst widely different species of 
animals and plants living under the same conditions; such as fleshiness of 
plants on sea coast, brassy tints of beetles ditto, and some similar cases 
which I observed in South America, such as transparency of wings in 
Heliconia butterflies living near either tropic; very suffused colouring on 
East of Andes under the equator, etc. 
““Some part of this general similarity is owing to natural selection 
adapting one species to another in external dress; but I think there are 
some cases where this explanation is inapplicable. 
‘‘TIt is curious in the case of negro, etc., that the colour produced by 
direct action should be also the one selected as most suitable by nature. 
‘‘Of course the whole argument depends on this question which you put, 
and which I thank you for having placed so vividly before me. 
‘‘Are the distinct peculiarities induced in the lifetime of an organism 
transmitted to its offspring? We may allow several generations for the 
operation. I cannot think of any facts giving affirmation to this question 
except the poor ones given in this letter. 
‘* Even if they prove it they would not show that a race and new species 
could be produced by direct action; natural selection is always acting and 
would act, of course, on the offspring of these species. 
‘©T am much, obliged to you for recalling me to order in the matter of 
forgetting the thousands of generations, and millions of individuals extin- 
guished without offspring in the case of insect species. I really was not 
giving the full force to that. 
‘«‘T have not fully answered your letter, but will finish another time. 
‘‘ Would you oblige me by getting from Mr. Bentham the names of the 
following trees? I think Mr. Spruce may have sent them under these same 
native names :—Tapiriba, a stone-fruit tree (very acid, common) ; Acutiriba, 
round yellow mealy fruit; Jabuti-putré-anonacez (?), delicious wild fruit; 
Massarandtba, cow tree; Umari, or Mari and Uixi, two similar fruits, Upper 
Amazons; Pama, wild stone fruit, flavour ofcherry ; Sucu-tba, of Santarem. 
‘Please give my kind regards to your family. 
“‘ Yours sincerely, 
‘‘H. W. BATES. 
«Will you please give me the reference to your remarks on colours of 
plants, and fur of arctic animals, not being dependent on climate? I must 
quote you in my book where I have given similar generalisation.’’ 
7c ee, dionker, 10.17. 1%... bates. 
“My DEAR MR. BATES, ‘““KEw, March 18th, 1862. 
‘*T have asked Mr. Bentham about the names of the Sprucean 
plants, but he has unfortunately kept no list of the native names; they are 
