To T. H. Huxley 8 March 1
Down Bromley Kent
My dear Huxley
When I feel myself chasing wild geese & get beyond my limited tether of knowledge, you always rise before me, as an awful bugbear, ready to pitch into me; & thus you do me great good service unintentionally. Now I have been thus thinking of you this morning & will you be so kind as to read over the enclosed queries & doubtful remarks—that is if you can understand at what I am driving, which is very doubtful.2
Further if you can answer me briefly I shd be much obliged; but if that be not possible, as is very probable, as the answer may require guarding & explaining, I beg you not to answer, but just say so; for I could leave out the two or three sentences, which I shd like to put in, or defer the subject till we meet, & I could hear how the truth lies vivâ voce.—3
I am working myself half to death to get my Abstract volume completed (which thank God it nearly is) & I sincerely hope that you are in different case from | Yours most truly | C. Darwin
(1) My impression is that in the whole Molluscan Kingdom we have not many (or any) clear cases of “serial homologies” in the same individual; like the skull in Vertebrata in relation to the vertebræ, or like jaws & segments of head in relation to legs & segments of body in the Articulata.
(2) My impression is that no mollusca, not even the lowest, offer good instances of a “vegetative repetition” (to use Owen’s ugly phrase)4 of parts of importance. The arms of Cephalopods seem (in my ignorance) chief exception, & we get some poor serial homologies in the arms of certain Cephalopods. I hypothetically wish to connect no 2. as cause of no 1.—5
(1) In single plant (ie in flower or leaf-bud) we often have many, almost indefinitely many, whorls of the same homological part; & in each separate whorl almost an indefinite number of such parts.— How far does this hold true with the Radiata, in the largest sense? In Encrinite can the stem be looked at as a pile of simple whorls; or is it not rather an elongated & modified footstalk of the single main whorl? In Radiata is not the number of important parts in each (the single?) whorl generally or always few & definite. Do the numerous tentacula in certain Actineæ or rays in certain Asteriases make a real exception; I fancy these tentacula (& rays) are only a vegetative repetition of an un important part, & not comparable to the repetition of stamens, pistils & petals of plants.—
I imagine that there are not good cases of “serial homologies” in individual species of the Radiata.— And this seems to be an odd contrast with plants.—6
Sends THH questions about "serial homologies" and "vegetative repetition" in Mollusca and Radiata.
Abstract volume [Origin] nearly completed.
Please cite as
Darwin Correspondence Project, “Letter no. 2425,” accessed on 12 February 2016, http://www.darwinproject.ac.uk/DCP-LETT-2425