Dr. Pelseneer, to whom the next letter is addressed, is a Belgian morphologist, and an authority upon the Mollusca. He it was who afterwards completed Huxley's unfinished memoir on Spirula for the "Challenger" report.] 4 Marlborough Place, June 10, 1890. Dear Dr. Pelseneer, I gave directions yesterday for the packing up and sending to your address of the specimens of Trigonia, and I trust that they will reach you safely. I am rejoiced that you are about to take up the subject. I was but a beginner when I worked at Trigonia, and I had always promised myself that I would try to make good the many deficiencies of my little sketch. But three or four years ago my health gave way completely, and though I have recovered (no less to my own astonishment than to that of the doctors) I am compelled to live out of London and to abstain from all work which involves much labour. Thus science has got so far ahead of me that I hesitate to say much about a difficult morphological question--all the more, as old men like myself should be on their guard against over-much tenderness for their own speculations. And I am conscious of a great tenderness for those contained in my ancient memoir on the "Morphology of the Cephalous Mollusca." Certainly I am entirely disposed to agree with you that the Gasteropods and the Lamellibranchs spring from a common root--nearly represented by the Chiton--especially by a hypothetical Chiton with one shell plate. I always thought Nucula the key to the Lamellibranchs, and I am very glad you have come to that conclusion on such much better evidence. I am, dear Dr. Pelseneer, yours very faithfully, T.H. Huxley. [Towards the end of June he went for a week to Salisbury, taking long walks in the neighbourhood, and exploring the town and cathedral, which he confessed himself ashamed never to have seen before. He characteristically fixes its date in his memory by noting that the main part of it was completed when Dante was a year old.] The White Hart, Salisbury, June 22, 1890. My dear Donnelly, Couldn't stand any more London, so bolted here yesterday morning, and here I shall probably stop for the next few days. I have been trying any time the last thirty years to see Stonehenge, and this time I mean to do it. I should have gone to-day, but the weather was not promising, so I spent my Sunday morning in Old Sarum--that blessed old tumulus with nine (or was it eleven?) burgesses that used to send two members to Parliament when I was a child. Really you Radicals are of some use after all! Poor old Smyth's death is just what I expected, though I did not think the catastrophe was so imminent. [Warrington Wilkinson Smyth (1817-1890), the geologist and mineralogist. In 1851 he was appointed Lecturer on Mining and Mineralogy at the Royal School of Mines. After the lectureships were separated in 1881, he retained the former until his death. He was knighted in 1887.]