As regards the vertebrate “bays,” Sir William himself (always of course with the aid of trained assistants) took an active part in the selection and arrangement of the specimens. In the case of the invertebrate groups, on the other hand, the task was left more to his subordinates; while as regards the botanical section such relegation was, of necessity, practically complete. Although it has been previously referred to elsewhere, it may be mentioned that it was during the work on the Index Museum the discovery of the absence in certain groups of birds of the fifth cubital quill-feather was made; a fact now familiar to naturalists under the title of diastaxy, or aquintocubitalism. A special feature of the vertebrate section of the Index Museum was the attention devoted to the mounting of the skins of the mammals exhibited. In an address delivered to the British Association in 1889, Flower referred to “the sadly neglected art of taxidermy, which continues to fill the cases of most of our museums with wretched and repulsive caricatures of mammals and birds, out of all natural proportions, shrunken here and bloated there, and in attitudes absolutely impossible for the creature to have assumed while alive.” And he was determined that the specimens of this nature in the section of the museum under his own immediate superintendence should be the best of their kind, and should serve as models for the renovation of these in the zoological galleries which he had determined to undertake so soon as the opportunity was afforded.