1859 LETTER TO LEUCKART 235 



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 * (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 ybur Memoir on 

 Pentastomum. There can be no difficult j' 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 work- 

 ing 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 Caly- 

 cophoridse 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, 



1 The present Lord Avebury. 



