In 1876 Professor Flower delivered before the Royal Institution an extremely interesting lecture on the extinct mammals of North America, which at that time were in course of being made known to the scientific world by the writings of Professors Marsh and Cope. In the course of this lecture Flower alluded at considerable length to the ancestry of the horse—then a comparatively new subject—and also discussed the structure and affinities of those gigantic many-horned mammals commonly known as Dinocerata. In concluding, the lecturer observed that the work accomplished in America taught us—“First, that the living world around us at the present moment bears but an exceedingly small proportion to the whole series of animal and vegetable forms which have existed in past ages. Secondly, that, notwithstanding all that has been said, and most justly said, of the necessary imperfection of the geological record, we may hope that there is still so much preserved that the study of the course of events which have led up to the present condition of life on the globe, may have a great future before it.” The subsequent discoveries of fossil mammalian remains in such enormous quantities in Patagonia, and still later in the Libyan desert, have rendered this utterance almost prophetic. During the same year (1876) appeared, in the _Philosophical Transactions_, a notice by Flower of the seals and cetaceans obtained during the _Transit of Venus_ expeditions of 1874 and 1875. The year 1876 likewise witnessed the publication, in the _Proceedings_ of the Zoological Society, of an article on the skulls of the various existing species of rhinoceroses, in which it was shown that the number of such species had been altogether unjustifiably exaggerated by the late Dr. J. E. Gray and other writers, and that in all probability there were really not more than five. Certain characters connected with the postero-lateral region of the skull were also described, which served to divide these species into groups. A further contribution to our knowledge of the skulls of the rhinoceroses was made by Flower in 1878, when he described, in the same journal, the skull of an Indian specimen, which it was thought might be the _Rhinoceros lasiotis_ of Dr. Sclater—now known to be (as then suggested) merely a local race of the two-horned _R. sumatrensis_.