The modern system of forming trinomials to indicate the local races, or sub-species, of mammals (as exemplified by _Giraffa camelopardalis rothschildi_ and _Giraffa camelopardalis capensis_ for two of the local phases of the species of giraffe typified by _G. camelopardalis_ of the Egyptian Sudan and Abyssinia), was practically in its infancy during the active life-time of Flower, and it is doubtful how he would have approved of the extent to which it has been subsequently carried. Nevertheless, that he appreciated the practice of recognising minute local differences of colour, size, etc., in the same species of mammals is evident from an incident within the writer’s own knowledge, which occurred at the Natural History Museum, when a tray containing the local phases of one of the species of the small squirrel-like rodents known as chipmunks was submitted to his notice; his remark being that such variations from a common type ought in nowise to be ignored, if we wished to make our knowledge of animals anything like complete, and that the simplest way of indicating such differences was to assign them distinct names. In a general way, however, it may be said that Sir William’s sympathies were with the wider and more philosophical aspects of zoology rather than with the details of specific and sub-specific distinction (which, by the way, have scarcely any more right to be regarded as real philosophical science than has stamp-collecting)[4]; and that, from a systematic standpoint, his interest was very largely concentrated on the relationships existing between the mammals of to-day and their extinct predecessors. Several of his lectures and papers, and one especially of his separate works (that on _The Horse_) were indeed devoted to this aspect of the subject; and on every possible occasion he emphasised his conviction of the necessity of studying (and arranging in museums) living and extinct mammals together, if we wish to make our science really practical. As a matter of fact he had the strongest possible objection to the recognition of “palæontology” as a science apart from zoology, and he even went so far as to mildly rebuke (in his own inimitably courteous and gentle manner) the present writer, for venturing to offer to the public a volume on that subject. To a great extent, no doubt, he was perfectly right in this contention, although there are points of view from which “palæontological” works are decidedly convenient, even if their existence and production cannot be logically justified.