many opportunities of working out in the course of our subsequent wanderings, so that I am provided with materials for a second paper far more considerable in extent, and embracing an altogether wider field.  This second paper is now partly in esse—­that is, written out—­and partly in posse—­that is, in my head; but I shall send it before leaving.  Its title will be “Observations upon the Anatomy of the Diphydae, and upon the Unity of Organisation of the Diphydae and Physophoridae,” and it will have lots of figures to illustrate it.  Now when we return from the north I hope to have collected materials for a much bigger paper than either of these, and to which they will serve as steps.  If my present anticipations turn out correct, this paper will achieve one of the great ends of Zoology and Anatomy, namely, the reduction of two or three apparently widely separated and incongruous groups into modifications of the single type, every step of the reasoning being based upon anatomical facts.  There!  Think yourself lucky you have only got that to read instead of the slight abstract of all three papers with which I had some intention of favouring you. [These papers are to be found in volume 1 of the “Scientific Memoirs” of T.H.  Huxley page 9.]

But five years ago you threw a slipper after me for luck on my first examination, and I must have you to do it for everything else.

[At the Cape a stay of a month was made, from March 6 to April 10, and certain surveying work was done, after which the “Rattlesnake” sailed for Mauritius.  In spite of the fact that the novelty of tropical scenery had worn off, the place made a deep impression.  He writes to his mother, May 15, 1847:—­]

After a long and somewhat rough passage from the Cape, we made the highland of the Isle of France on the afternoon of the 3rd of this month, and passing round the northern extremity of the island, were towed into Port Louis by the handsomest of tugs about noon on the 4th.  In my former letter I have spoken to you of the beauty of the places we have visited, of the picturesque ruggedness of Madeira, the fine luxuriance of Rio, and the rude and simple grandeur of South Africa.  Much of my admiration has doubtless arisen from the novelty of these tropical or semitropical scenes, and would be less vividly revived by a second visit.  I have become in a manner blase with fine sights and something of a critic.  All this is to lead you to believe that I have really some grounds for the raptures I am going into presently about Mauritius.  In truth it is a complete paradise, and if I had nothing better to do, I should pick up some pretty French Eve (and there are plenty) and turn Adam.  N.B.  There are no serpents in the island.