ORDER VII. The CETA, or whale kind, have no uniform character in their teeth, being very different in the different genera; but are sufficiently distinguished from the other orders of Mammalia, by living in the ocean, having pectoral fins, and a fistula or spiraculum upon the head.—This order includes 4 genera, viz. Monodon, Balena, Physeter, Delphinus. See CETACEOUS.
The generic characters of the Mammalia are, like those of the orders, almost entirely taken from the TEETH, excepting the Vespertilio, which, besides the character of the order derived from the teeth, has this further mark, that there is a membrane attached to the feet and sides, by means of which the creature is enabled to fly:—the Hystrix, whose body is covered with sharp spines;—and the whole order of Pecora, whose genera, besides the characters taken from the teeth, are distinguished into those which have horns, those which have no horns, and by peculiarities in the horns themselves.
The specific characters are very various, being taken from any part of the body which possesses a peculiar uniform mark of distinction. As examples of these characters are to be found under the proper name of each genus, it is unnecessary to say any thing further concerning them in this place.
The Second Class, AVES, is subdivided into six ORDERS; the characters of which are taken chiefly from the structure of the BILL.