About this time the Natural History Museum received a series of antlers shed year by year by one particular red-deer stag, together with the complete skull and antlers of the same animal; and this gift induced Flower to deliver in December 1887 a lecture on “Horns and Antlers” before the Middlesex Natural History Society, which is printed, with a plate of the aforesaid series of red-deer antlers, in a somewhat abbreviated form, in the _Transactions_ of that Society. If we except a few on Cetacea, noticed in the next chapter, Sir William’s contributions to the Zoological Society’s _Proceedings_ after 1883 were not numerous or of much importance. In 1884 he contributed, however, remarks on the so-called white elephant from Burma, then exhibited in the Society’s Menagerie; and in the same year he also wrote on the young dentition of the capybara. In 1887 he discussed the generic position and relationships of the pigmy hippopotamus of Liberia. The acquisition in the following year by the Natural History Museum of specimens of that breed of Japanese fowls remarkable for the excessive elongation of the tail-feathers of the cocks, led to a note on that subject in the _Proceedings_ for the same year. This paper, it may be incidentally mentioned, is noteworthy, on account of the evidence it affords that Sir William did not regard the variations displayed by domesticated animals as in any way unworthy the notice of the naturalist; while the next shows that monstrosities or abnormalities—at all events to a certain extent—are also worthy of recognition. The note incidentally alluded to in the last sentence appeared in 1889, and dealt with an African rhinoceros head, showing three horns. Finally, in 1890, Sir William exhibited and commented upon a photograph of the nesting-hole of a hornbill, showing the female “walled up” with mud. The next year (1891) saw the publication of _An Introduction to the Study of Mammals, Living and Extinct_, written, as already said, in collaboration with the present writer, and embodying the whole of Flower’s contributions to the _Encyclopædia Britannica_, together with certain articles by other authors from the same work, and such new material as was necessary in order to weave these _disjecta membra_ into one connected and harmonious whole. In the same year was also published, in the _Modern Science Series_, Sir William’s admirable little volume on _The Horse_, which was likewise largely based on his _Encyclopædia_ articles. In this work Flower dwelt particularly on the vestiges exhibited by the modern horse of its descent from more generalised ancestors; and he was successful in demonstrating that the structure known to veterinarians as the “ergot,” represents one of the foot-pads of the earlier forms.