work, but I have not flinched when there was anything to be done.

Under these circumstances you will imagine that it was very pleasant to
find on your side a recognition of what I was about.

I sent you, through the booksellers, some time ago a copy of my memoir
on Aphis. I find from Moleschott's "Untersuchungen" that you must have
been working at this subject contemporaneously with myself, and it was
very satisfactory to find so close a concordance in essentials between
our results. Your memoirs are extremely interesting, and to some extent
anticipated results at which my friend, Mr. Lubbock [The present Sir
John Lubbock, M.P.] (a very competent worker, with whose paper on
Daphnia you are doubtless acquainted), had arrived.

I should be very glad to know what you think of my views of the
composition of the articulate head.

I have been greatly interested also in your Memoir on Pentastomum. There
can be no difficulty about getting a notice of it in our journals, and,
indeed, I will see to it myself. Pray do me the favour to let me know
whenever I can serve you in this or other ways.

I shall do myself the pleasure of forwarding to you immediately, through
the booksellers, a lecture of mine on the Theory of the Vertebrate
Skull, which is just published, and also a little paper on the
development of the tail in fishes.

I am sorry to say that I have but little time for working at these
matters now, as my position at the School of Mines obliges me to confine
myself more and more to Paleontology.