Ɛpsilon

From W. D. Crick   24 February 1882

111 Overstone Road | Northampton

Feb 24th. 82

Dear Sir

I think the shell is Sphærium corneum but cannot be quite sure, it measures .35 of an inch from the beaks to front margin .45 of an inch from one side of the valve to the other, and .3 of an inch in depth and weighs .39 gramme.1

I am sorry that the shell dropped off the bettle on Thursday 23rd. inst afternoon and I caught it on the Saturday 18th. inst. afternoon previous, it was very firmly fixed for the beetle shook it violently in its movements and a little while after they had separated the bettle dived to the bottom and its left antenne was caught between the valves and the bettle was held for a few minutes apparently unable to rise, in its original position the shell was on the right hand side of the bettle, looking down upon the bettle with the head away from the observer, on the 2nd. or imtermediate leg, four joints of the tarsus were visible and the remainder of the foot measures .1 of an inch.

The beetle was captured in a small pond and was able to crawl easily through grass but it never attempted to fly that I am aware of sine I have had it, both the specimens are forwarded to you alive by accompanying post and I hope they will arrive safely, as you think the case worth communicating to Nature should be pleased to do so but should like to be certain about the shell first, if there is any other information you require I should be pleased to supply if possible2

Very truly yours | W. D. Crick

Chas Darwin Esq.

CD annotations

Verso of last page: ‘Shell alive 25th 2°30′ P.M.: when first put at water | 27th. Trawl about in sand at bottom of vessel.’ pencil; ‘My son F. & a companion while fishing off the coast often brought up small mussels, and it was their joint impression that the tip had been seized by the shell fish & though it held on so hard that the byssus had been torn.—’3 black ink
1
See letter to W. D. Crick, 21 February 1882 and n. 1. Sphaerium corneum is the European fingernail clam.
2
CD communicated the case to Nature, but the clam was identified as Cyclas cornea (a synonym of Sphaerium corneum) (‘Dispersal of freshwater bivalves’).
3
CD’s annotations are notes for his reply of 25 February 1882. Francis Darwin is the son mentioned. He had been salmon fishing in north Wales in October 1881 (see Correspondence vol. 29, letter from Francis Darwin, [21 October 1881]).

Please cite as “DCP-LETT-13705,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-13705