The grouping of animals by structural characters, and by affinities which are assumed, though based on almost undeniable evidence, whether into species, families, classes, phyla or sub-phyla, has its apotheosis in Mollusca and Insects. As to the second of these immense groups it has always seemed strange that their colourings and structural characters should have received such intensive study from Weismann to the exclusion of Mollusca, when he set out to prove his stupendous negative, and still more that of Vertebrates, among which his chief difficulty and desired triumph would seem to have lain. Mollusca though invertebrate are held by many to be in the line of ancestry of the highest forms of life, and at any rate insects are not. They are most fruitful fields indeed in which Nature has been able to show what she could do by her stern selective powers, but, from the point of view of descent with modification, may be fairly compared to a review of an army in time of peace, or the Kriegspiel of a German military staff. He who concerns himself with the fundamental difficulties of the problems at issue in evolution must make his notes of what experts tell him of such groups as those of Insects, Mollusca and Birds, and pass on to the higher forms in which on the one hand function becomes the predominant partner, and on the other individual experience becomes more and more important. He feels indeed at liberty to wish the entomologist and ornithologist all success, and to leave him at peace, in his siding, to pursue his delightful and interminable studies far from the dust and din of controversy. Insectivores.