Of this branch of work Sir M. Foster says: (Obituary Notice "Proceedings of the Royal Society" volume 59):—

One great consequence of these researches was that science was enriched by a clear demonstration of the many and close affinities between reptiles and birds, so that the two henceforward came to be known under the joint title of Sauropsida, the amphibia being at the same time distinctly more separated from the reptiles, and their relations to fishes more clearly signified by the joint title of Ichthyopsida. At the same time, proof was brought forward that the line of descent of the Sauropsida clearly diverged from that of the Mammalia, both starting from some common ancestry. And besides this great generalisation, the importance of which, both from a classificatory and from an evolutional point of view, needs no comment, there came out of the same researches numerous lesser contributions to the advancement of morphological knowledge, including among others an attempt, in many respects successful, at a classification of birds.

This work in connection with the reptilian ancestry of birds further appears in the paleontological papers published in 1869 upon the Dinosaurs (see Chapter 23), and is referred to in a letter to Haeckel.

His Hunterian lectures on the Invertebrata appeared this year in the "Quarterly Journal of Microscopical Science" (pages 126-129, and 191-201), and in the October number of the same journal appeared his famous article "On some Organisms living at great depth in the North Atlantic Ocean," originally delivered before the British Association at Norwich in this year (1868). The sticky or viscid character of the fresh mud from the bottom of the Atlantic had already been noticed by Captain Dayman when making soundings for the Atlantic cable. This stickiness was apparently due to the presence of innumerable lumps of a transparent, gelatinous substance, consisting of minute granules without discoverable nucleus or membranous envelope, and interspersed with cretaceous coccoliths. After a description of the structure of this substance and its chemical reactions, he makes a careful proviso against confounding the statement of fact in the description and the interpretation which he proceeds to put upon these facts:—]

I conceive that the granulate heaps and the transparent gelatinous matter in which they are embedded represent masses of protoplasm. Take away the cysts which characterise the Radiolaria, and a dead Sphaerozoum would very nearly represent one of this deep-sea "Ur-schleim," which must, I think, be regarded as a new form of those simple animated beings which have recently been so well described by Haeckel in his "Monographie der Moneras" page 210. [(See "Collected Essays" 5 153.)

Of this he writes to Haeckel on October 6, 1868:—]

This paper] is about a new "Moner" which lies at the bottom of the Atlantic to all appearances, and gives rise to some wonderful calcified bodies. I have christened it Bathybius Haeckelii, and I hope that you will not be ashamed of your god-child. I will send you some of the mud with the paper.

[The explanation was plausible enough on general grounds, if the evidence had been all that it seemed to be. But it must be noted that the specimens examined by him and by Haeckel, who two years later published a full and detailed description of Bathybius, were seen in a preserved state. Neither of them saw a fresh specimen, though on the cruise of the "Porcupine," Sir Wyville Thomson and Dr. W. Carpenter examined the substance in a fresh state, and found no better explanation to give of it. However, not only were the expectations that it was very widely distributed over the Atlantic bottom, falsified in 1879 by the researches of the "Challenger" expedition, but the behaviour of certain deep-sea specimens gave good ground for suspecting that what had been sent home before as genuine deep-sea mud, was a precipitate due to the action on the specimens of the spirit in which they were preserved. Though Haeckel, with his special experience of Monera, refused to desert Bathybius, a close parallel to which was found off Greenland in 1876, the rest of its sponsors gave it up. Whatever it might be as a matter of possibility, the particular evidence upon which it had been described was tainted. Once assured of this, Huxley characteristically took the bull by the horns. Without waiting for any one else to come forward, he made public renunciation of Bathybius at the British Association in 1879. The "eating of the leek" as recommended to his friend Dohrn (July 7, 1868), was not merely a counsel for others, but was a prescription followed by himself on occasion:—]

As you know, I did not think you were on the right track with the Arthropoda, and I am not going to profess to be sorry that you have finally worked yourself to that conclusion.

As to the unlucky publication in the "Journal of Anatomy and Physiology," you have read your Shakespeare and know what is meant by "eating a leek." Well, every honest man has to do that now and then, and I assure you that if eaten fairly and without grimaces, the devouring of that herb has a very wholesome cooling effect on the blood, particularly in people of sanguine temperament.