ROD

A measure of length, otherwise called a pole. It is 6^ yards, or 16^ feet; and four of these make the Gunter's chain. RODENTS, JRorf(?w«?a. (Lat. rodo, 7 ^naii'.) The name given by Cuvier to the Glires of Linna;u8, an order of Unguiculate Mammals, comprehending those which have two long chisel-shaped incisors in each jaw, and no canines, but a vacant interspace between the incisors and the molars; the lower jaw is articulated by a longitudinjil condyle, in such a way as to allow of no horizontal motion, except from back to front, and vice vers a, as is requisite for the action of gnawing. The molars also have flat crowns, whose enamelled eminences are always transverse, so as to be in opposition to the horizontal motion of the jaw, and to increase the power of trituration. The genera in which these eminences are simple Jines, and the crown is very flat, are more exclusively frugivorous; those in which the eminences of the teeth are divided into blunt tubercles are omnivorous; while the small number of such as have no points more readily attack other animals, and approximate somewhat to the Carnaria. The form of the body in the Rodent i a is generally such that the hinder parts of it exceed those of the front, so that they rather* leap than walk. In some of them this disproportion is even as exce ive as it is in the kangaroos. In the whole of this cla the brain is almost smooth, and without furrows; the orbits are not separated from the temporal fo ae, which have but little depth; and the eyes are altogether lateral. The inferiority of these animals is visible in most of the details of their organization. Those genera, however, which po e stronger clavicles have a certain degree of dexterity, and use their fore feet to convey their food to the mouth. [s. 1075]