as they passed them, at a bite, just a little above the vent, so that they themselves escaped the swallowed hook; and I have frequently lost, in this way, no inconsiderable portion of a fishing. I have observed, however, he continued, that when a fresh pack of hungry dog-fish came up, and joined the pack that had been robbing us so coolly, and at their leisure, a sudden rashness would seize the whole,—the united packs would become a mere heedless mob, and, rushing forward, they would swallow our fish entire, and be caught themselves by the score and the hundred. We may see something very similar to this taking place among even the shrewder mammalia. When pig refuses to take his food, his mistress straightway calls upon the cat, and, quickened by the dread of the coming rival, he gobbles up his rations at once. With the comparatively large development of brain, and the corresponding manifestations of instinct, which the true Placoids exhibit, we find other unequivocal marks of a general superiority to their class. In their reproductive organs they rank not with the common fishes, nor even with the lower reptiles, but with the Chelonians and the Sauria. Among the Rays, as among the higher animals, there are individual attachments formed between male and female: their eggs unlike the mere spawn of the osseous fishes, or of even the Batrachians, are, like those of the tortoise and the crocodile, comparatively few in number, and of considerable size: their young, too, like the young of birds and of the higher reptiles, pass through no such metamorphosis as those of the toad and frog, or of the amphibia generally. And some of their number—the common dog-fish for instance—are ovoviviparous, bringing forth their young, like the common viper and the viviparous lizard, alive and fully formed. “But such features,” says the author of the “Vestiges,” referring chiefly to certain provisions connected with the reproductory system in the Placoids, “are partly partaken of by families in inferior sub-kingdoms, showing that they cannot truly be regarded as marks of grade in their own class.” Nay, single features do here and there occur in the inferior sub-kingdoms, which very nearly resemble single features in the placoid character and organization, which even very nearly resemble single features in the _human_ character and organization; but is there any of the inferior sub-kingdoms in which there occurs such a _collocation_ of features? or does such a collocation occur in any class of animals—setting the Placoids wholly out of view—which is not a high class? Nay, further, does there occur in any of the inferior sub-kingdoms—existing even as a single feature—that most prominent, leading characteristic of this series of fishes,—a large brain?