Dear Sir

Instead of being a trouble it is a pleasure to answer your enquiries, the shell was fixed to the leg of the bettle from the 18^th. to the 25^th., the beetle when caught was kept for about 3 hours in a handkerchief but after then was kept in water and it was when in the water that the bettle was caught for a few minutes by its antenne, the shell was alive when it dropped from the bettle and had its siphons extruded when the bettle dived down to the bottom of the vessel and thrusting its antenne between the valves which closing upon it, was held there for a few minutes.¹

You are quite welcome to keep the specimens as long as you care to, and do with them whatever you think proper

The gentlemen who was with me on the occasion of capturing the beetle tells me he has often caught mussels when fishing in rapid streams but they have never been very large.

It may be interesting to know that an individual of the same species of shell and about the same size as the one forwarded to you has extruded two young ones which seem very active and able to take care of themselves; according to D^r. J G Jeffreys in British Conchology Vol 1 Introduction Page XXV and page 1, all bivalves are monœcious and able to fertilize themselves so that it is only necessary for one individual to be removed to a new locality for it to become stocked.²

Pardon me also for calling your attention to a remark in the same volume in the introduction page LXXX viz. “This diffusion of freshwater shells has been attributed to the chance transport of birds; but I am inclined to believe that it had a different and very remote origin, and that it took place long before the present distribution of land and water”.³

I remain | Yours very truly | Walter. D. Crick

Chas. Darwin Esq.