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Darwin Correspondence Project

From Robert McAndrew   6 October 1855


6th. October | 1855

My dear Sir

I have received your very kind note of yesterdays date, & beg to say in reply to your first question,1 that in “typical” I have very probably made use of a wrong word— the forms I allude to are such as Buccinum undatum, & allied species (B. Ciliare, B Humphreysianum, B. Cyaneum, B. Fusiforme &c.)— Fusus Antiquus, F Icelandicus, F propinquus &c.— The Genus Trichotropis—subgenus MargaritaPurpura lapillus— & among bivalves Cyprina Islandica—& the genera Saxicava, Astarte, Leda, Yoldia, Crenella &c.— which are principally develloped in the Arctic Seas, & are considered to be characteristic of these, as the larger Cyprææ, Conus, Voluta, Mitra &c. of the tropical regions.

With respect to your second question2 I have to state that it has never been my lot to fall in with drift timber—other than what had been used in the construction of vessels, either at sea or upon the Coasts of Britain, though I give no opinion against the statements of its being occasionally washed ashore upon the Coasts of Ireland & of the Western Hebrides—which indeed appears to me highly probable—

I never heard of vessels at sea striking against floating timber other than wreck—& I do not believe that timber ever floats under the surface, though it will after a long time, get saturated with water & sink to the bottom, where if not in too great a depth, it eventually gets destroyed by the Teredo, Xylophaga—Pholades &c.

It will at all times afford me the greatest pleasure to be enabled in any way to assist you in your researches—though my ability for it can be but small—

Believe me always | My dear Sir | Yours most truly | Robt. Mc.Andrew Chas. Darwin Esqr.


CD had apparently written to McAndrew after reading his work on the geographical distribution of testaceous Mollusca (McAndrew 1854), an annotated copy of which is in the Darwin Pamphlet Collection–CUL. The gist of CD’s query was reiterated in his annotation on the top of the letter (see CD annotations, above) and refers to McAndrew’s comment in McAndrew 1854, p. 44, that ‘it will appear that several species and forms typical of the Arctic fauna range far to the southward, while scarcely one of those characteristic of warm latitudes extends into high northern regions.’ In his copy of the pamphlet, CD underlined the word ‘typical’ in pencil and noted: ‘does typical here mean common? or belonging to genera which are arctic’.
CD apparently asked McAndrew whether molluscs could be transported across the sea attached to driftwood. At the top of a memorandum attached to his copy of McAndrew 1854, CD wrote: ‘Mr Macandrew told me that some of the Littorina are viviparous. We ought to know how long eggs are hatching— how long larva exist in free state— whether eggs ever attached on old shells to floating weed or drift timber.’ To try to ascertain this point, CD set up a vivarium (see letter to John Lubbock, 24 April [1855]).


Answers questions presumably sent in CD’s letter [missing] of 5 Oct 1855 after reading RMcA’s work on the geographical distribution of testaceous Mollusca.

Letter details

Letter no.
Robert McAndrew
Charles Robert Darwin
Sent from
Source of text
DAR (Pamphlet collection: bound in McAndrew, Robert 1854)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 1759A,” accessed on 26 January 2020,

Also published in The Correspondence of Charles Darwin, vol. 5