Page:Popular Science Monthly Volume 2.djvu/159

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istence in certain animals, both fossil and recent, of two sets of traits—one proper to, and marking their peculiar individuality as members of an order, tribe, or family; and the other set, although found in them, yet destined to a fuller unfolding in animals yet to be created, and to mark their peculiarities. In a word, the species in question was regarded as looking forward to or foreshadowing, in these seemingly eccentric traits, the characteristics of tribes yet to come. As, for example, take the ancient Ganoids, or fishes, covered with shining, bony scales, as the word signifies. Their common representative, now, is the sturgeon, which, though a fish, has structural and physiological points that belong to the reptiles. Regarding these curious traits as put together in one individual, and in a sense to be yet separated from it, and specialized in other and higher animals, Agassiz invented, felicitously, as we think, a term to express these facts, namely, "synthetic type." Dana prefers the phrase "comprehensive type," and Guyot uses the term "undivided type."

The study of this almost grotesque little animal has proved singularly suggestive of certain points of structure and habit, usually regarded as peculiarities of other animals. In Nasua are found features which elsewhere are sufficiently dominant to warrant generic distinction—as the architect can specify certain points in the Composite order which are derived from several other orders. To designate the parts that make up this strange unity in our subject may not be easy. The botanist is, at times, perplexed in his effort to formulate the specific distinctions of a simple plant. Let him take an oak, for example—and it may be that the analysis is unsatisfactory; yet the specific conception of the tree, taken from its contour and entirety, may, for all that, be quite trustworthy. To the writer, the Nasua, viewed as a whole in the matter of structure, form, and habit, has appeared to be a synthetic, or comprehensive type—not, perhaps, a composite, as made up of what had been before, but possibly typical of what was to come. Limited strictly to anatomical analysis, the typical range would be narrowed; but, studied in the above more exhaustive method, the diagnosis must, we think, be highly significant. It may appear a superficial resemblance that is presented in the ornamentation of the respective tails of the coati and the raccoon. But these animals have also anatomical parallels of structure. Both have a similar dental arrangement, and both have plantigrade limbs. Here, again, the coati, with the coon, becomes cousin to the bear, for all three have that structure which compels that setting down at once the entire great sole of the foot, and that walking thereon, which the books denominate plantigrade. The three, also, have similarly-shaped heads, similar small eyes, small, trim ears, and peculiar claws, which are, all and several, known as ursine traits. They have also not unlike appetencies of food. They are plantigrade carnivora, and have in common a striking habit which removes them from the pure or digitigrade car-