[Illustration: Strange and Rare Fishes 1, Diodon; 2, Rhinobatus; 3, Tetrodon; 4, Galaxias; 5, Pterois; 6, Ostracion; 7, Pelor; 8, Amia; 9, Haplochiton; 10, Callionymus; 11, Cottus; 12, Malthe; 13, Blennius; 14, Pomacentrus; 15, Chromis; 16, Scorpæna] Let me say a word as to the general insect type. It may be described shortly as consisting of animals possessing a head, with mouth-parts, eyes, and antennæ; a many-segmented body, with three pairs of legs on the segments immediately following the head; with, when mature, either one or two pairs of wings, generally with caudal appendages. Thus, then, we find in many of the principal groups of insects that, greatly as they differ from one another in their mature condition, when they leave the egg they more nearly resemble the typical insect type, consisting of a head, a three-segmented thorax, with three pairs of legs, and a many-jointed abdomen, often with anal appendages. Now, is there any mature animal which answers to this description? We need not have been surprised if this type, through which it would appear that insects must have passed so many ages since (for winged Neuroptera have been found in the carboniferous strata), had long ago become extinct. Yet it is not so. The interesting genus Campodea still lives; it inhabits damp earth, and closely resembles the larva of Chloëon, constituting, indeed, a type which occurs in many orders of insects. It is true that the mouth-parts of Campodea do not resemble either the strongly mandibulate form which prevails among the larvæ of Coleoptera, Orthoptera, Neuroptera, Hymenoptera, Lepidoptera; or the suctorial type of the Homoptera and Heteroptera. It is, however, not the less interesting or significant on that account, since its mouth-parts are intermediate between the mandibulate and haustellate types; a fact which seems to me most suggestive. It appears, then, that there are good grounds for considering that the various types of insects are descended from ancestors more or less resembling the genus Campodea, with a body divided into head, thorax, and abdomen; the head provided with mouth-parts, eyes, and one pair of antennæ; the thorax with three pairs of legs; and the abdomen, in all probability, with caudal appendages. If these views are correct, the genus Campodea must be regarded as a form of remarkable interest, since it is the living representative of a primeval type, from which not only the Collembola and Thysanura, but the other great orders of insects have derived their origin.