[Illustration: FIG. 85--_Præanaspides præcursor_, ONE OF THE FOSSIL SYNCARIDA, FROM THE COAL-MEASURES OF DERBYSHIRE. SLIGHTLY ENLARGED. (After H. Woodward.)] It must be pointed out that, in spite of the resemblance of the body of _Anaspides_ to that of an Amphipod, the Syncarida can have had no close relation to the origin of the Isopoda and Amphipoda. These have also been derived from a shrimp-like type, but their possession of a brood-pouch, among other characters, shows that they are linked on to the Mysidacea, and must have arisen from some primitive member of that group, like _Pygocephalus_. Although palæontology as yet gives little help in tracing the course of their evolution, we can imagine what the intermediate links must have been like by comparison with the living Cumacea and Tanaidacea. It is possible, indeed, that the divergence of the Isopod line of descent from that of the Mysidacea took place earlier than the Carboniferous epoch, for there has recently been discovered in rocks of Devonian age in Ireland a single specimen of a fossil, to which the name of _Oxyuropoda_ has been given, which has every appearance of being an Isopod. At all events, undoubted Isopods make their appearance in rocks of the Secondary Period, and some of those from the Jurassic epoch are not very different in general form from types still existing. Some of the Carboniferous shrimp-like Crustacea present characters which seem to point in the direction of the Stomatopoda, and fossils which clearly belong to that group are found in Jurassic and later deposits. In the Cretaceous epoch there were Stomatopoda resembling modern types so closely that they have been referred to the existing genus _Squilla_. We are even able to say that they resembled the living Stomatopoda in their mode of development, for larvæ of the type known as _Erichthus_ have been recognized in rocks of Cretaceous age from Lebanon. This is a striking example of the way in which, by a fortunate accident as it were, organisms apparently ill-adapted for fossilization may occasionally be preserved.