To Albany Hancock [26 January – March 1850]1
Down Farnborough Kent.
My dear Sir
I am ashamed at myself to think how long I have taken to send you my Mollusca:2 I have now got them in a Bottle, & will send with them a catalogue of localities; there about 60 packets, though some are duplicates— I send with them the rudest notes of colour & size made at time.3 The colours are given by comparison with Pat. Symes’ nomenclature.4 The notes are those of an ignorant schoolboy as I was almost then, & shamefully written; I wd have copied them out, if they had had any value.— Will you nevertheless please preserve these notes, for as one sometimes likes to see an old book, so I like to keep my wretched zoological notes.— I fear my specimens can be of hardly any interest to you; they must be so shrunk from the Spirits— I think there are one or two new genera— I will despatch the Box with large bottle on next Wednesday,—the first day our Carrier goes.— You will understand I do not want specimens ever returned.— If there shd be any part of M.S. which you by chance shd wish to read, I will with pleasure copy it.—
Very many thanks for the Clitia:5 it has astonished me & convinced me of my ignorance.— I entirely give up the burrowing of your Alcippe & my Arthrobalanus, I only do not give up Lithotrya6 from its large mishapen cup being so ill-formed for burrowing & from its having a beautiful rasping apparatus. How difficult it is to discuss any point by letter; I now see that I omitted to mention to you, that all round the base (& therefore widest part) of the head or shell on the top of the peduncle, there is a beautiful rasping rim or circular toothed saw;—renewed moreover, during every moult when the shell & animal increases in size, & as the peduncle has great power to lengthen & shorten & twist itself about, I cannot doubt if you were to fix a young Lithotrya at the bottom of a deep hole of the diameter of a pin or straw, during growth the animal wd be enabled to enlarge it to any extent. I confess I am quite puzzled by Clitia; it appears to me from your specimens, (which I must hereafter further examine) that the whole of the corrosion is effected round the margin of the base; that is, that no corrosion or wear goes on except round the growing basal edges— did you come to this conclusion? I cannot doubt that the shell is so fixed that it cannot move; certainly there are no sharp points on basal membrane as I have formerly examined it under high power.— Does not your fact of the Modiola show that the action is effected by solution, or at least not mechanically.—7
You ask me about Goodsir’s male Balanus; it is quite a mistake— his male Balanus is a female crustacean allied to Bopyrus & his parasite is the male of this female.—8 But now comes the odd case, I have found two genera of cirripedes with males separate & parasitic on the females;9 in these cases I am sure there can be no mistake, though I will not take up your time with details.—
I have not yet!! looked at Alcippe for ever since writing last to you, my two-hour-per day-work has been occupied with a tiresome set of fossils.— I have the curious Alepas squalicola sent me from Copenhagen,10 but I have not looked at it yet.—
Yours very sincerely | C. Darwin
Discusses mollusc specimens and related notes sent to AH. Thanks him for cirripede specimens. Discusses various cirripede species.