covered with armour of thickly tuberculated bony plates, and both furnished with a vertebrated tail." Our author compares Coccosteus to a boy's kite, a simile which, from the figure,[1] appears sufficiently apt. The arms are much more like fins or paddles than those of Pterichthys; and indeed, exhibiting as they do an approach to the normal form of a fish's fin, rather militate against the hypothesis already noticed as suggested by Agassiz, that these organs in Pterichthys were merely weapons of defence. The author, as well as many other geologists, lays great stress on the similarity in outline between these anomalous fishes and the extinct trilobites, thus hypothetically connecting the fishes with the Crustacea. It is not the province of a notice like this to enter on so abstruse a question, but the premises on which the hypothesis is founded, seem scarcely available in such a cause. Let it be first solved whether a trilobite belonged to the mollusk or crustaceous province of the animal kingdom,—whether it crawled on its belly like a snail, darted through the water like a shrimp, or ran on dry ground like a spider. After ascertaining these particulars, let us attempt a comparison between it and other animals by characters less superficial than mere outline or appearance, something a little more structural than the resemblance of an orchis to a bee or a mantis to a leaf. Indeed Mr. Miller, although yielding to the idea of thus connecting the fishes with the Crustacea, evinces a much sounder mode of thinking when he speaks of the resemblance, even when more striking, as "pictorial." After speaking of the body of the trilobite as being really jointed, he tells us the body of Cephalaspis was barred by transverse scales, between which there were no joints, and concludes his observations in these words. "It is interesting to observe how nature, in thus bringing two such different classes as fishes and Crustacea together, gives to the higher animal a sort of pictorial resemblance to the lower, in parts where the construction could not be identical without interfering with the grand distinctions of the classes."—p. 79.
We are next introduced to fishes whose figure is somewhat more in accordance with our notions of what a fish ought to be, yet differing most essentially in some structural peculiarities. The readers of the Zoologist must be well acquainted with the common sturgeon, and must have observed the manner in which its head and sides are defended with osseous plates: the same character is still more observ-
- ↑ In our copy of the figure a portion of the tail has been drawn detached from the body, in order to save the space which so long a block would have required.
