I learned the meaning of Morphology and the value of development as the criterion of morphological views—­first, from the study of the Hydrozoa during a long voyage, and secondly, from the writings of Von Baer.  I have done my best, both by precept and practice, to inaugurate better methods and a better spirit than had long prevailed.  Others have taken the same views, and I confidently hope that a new epoch for zoology is dawning among us.  I do not claim for myself any great share in the good 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.

However, I keep to the anatomical side of that sort of work, and so, now and then, I hope to emerge from amidst the fossils with a bit of recent anatomy.

Just at present, by the way, I am giving my disposable hours to the completion of a monograph on the Calycophoridae and Physophoridae observed during my voyage.  The book ought to have been published eight years ago.  But for three years I could get no money from the Government, and in the meanwhile you and Kolliker, Gegenbaur and Vogt, went to the shores of the Mediterranean and made sad havoc with my novelties.  Then came occupations consequent on my appointment to the chair I now hold; and it was only last autumn that I had leisure to take up the subject again.

However, the plates, which I hope you will see in a few months have, with two exceptions, been engraved five years.

Pray make my remembrances to Dr. Eckhard.  I was sorry not to have seen him again in London.