Next came the question of the nature of the so-called "clavicle." The determination of the structure of the shoulder-girdle threw open the homology of this bone, which clearly could not be a clavicle, whatever else it might be. The alternative position once more lay in the pelvis, and this time between the ischium and the pubis; and as the ilium was bird-like, might not the ischium, or pubis, be also expected to be ornithic in form? At any rate the bone answered remarkably well to the ischium of one of the Ratitæ.
Resemblances to the structures found in some birds had already been noted by Prof. Owen[1] in the sacrum of the Dinosauria; but these specially ornithic peculiarities of the pelvic girdle had not been indicated by any anatomist, and opened up a very interesting field of inquiry. To this I devoted all my disposable leisure during the winter of 1867–8, occupying myself chiefly with a critical examination of the materials in the British Museum in order to ascertain how far the peculiarities of Megalosaurus were common to the Dinosauria in general. As I knew that Prof. Phillips had devoted a great deal of time and thought to the collection which he has done so much to form, I begged him to furnish me with a statement of the results at which he had arrived before my visit; and in the commencement of 1868 he favoured me with the following letter:—
"My dear Huxley.—I must no longer delay to send you a notice of some specimens of Megalosaurian bones in this Museum, and of the doubts which frequent examination of them had raised in my mind touching the true composition of the skeleton. Since I had the opportunity of speaking to you on this matter, with the specimens before us, you have made so much progress toward replacing doubts by decisions, that, in truth, there is little now to be said which can appear to you either new or important. Still it will be a plea- sure to me to recall the process by which I was led to form a quite different idea of Megalosaurus from that which I had derived from Cuvier and Buckland—the great early and skilful explorers in this field. When I came to reside in Oxford, and to handle the noble collection of Dr. Buckland, I was speedily satisfied that only two groups of reptilian bones were frequent at Stonesfield and in the contemporaneous (geologically speaking) Oolitic beds of the vicinity, viz. Megalosaurus and Teleosaurus. To these must be added, as usually of somewhat later date, Cetiosaurus of Owen, and, still later, for the most part, Steneosaurus. Teleosaurus and Steneosaurus require scrutiny to be differentiated; the bones of Cetiosaurus in this collection are more easily separated from those of Megalosaurus; but there are not many homologous bones of these two reptiles in our collection, rich as it really is. I mention these things chiefly to satisfy you that, exceptis excipiendis, the large case which you
- ↑ Prof. Owen evidently attached no weight to the fact as indicating any affinity of the Dinosauria with birds, as in his 'Report on British Fossil Reptiles,' 1861, p. 102, he says that "the Reptilian type of structure makes the nearest approach to Mammals in the Dinosauria."
