The trunk is divided into two regions—an anterior thorax, or chest, (enclosed in the bony cage formed by the ribs, sternum, and the adjoining part of the vertebral column), and a posterior abdomen. The two cavities are divided from each other by a fleshy partition called the diaphragm. Organs of special sense.—In addition to the sense of touch which is possessed by the whole surface of the body, the rabbit has organs which enable it to distinguish objects by sight, sounds, scents, and taste. Its sense of smell is so keen that, to be successful in snaring rabbits, “in walking to the spot selected for the snare it is best to avoid even stepping on the run, and while setting it up to stand back as far as convenient and lean forward. The grass that grows near must not be touched by the hand, which seems to impart a very strong scent. The stick that has been carried in the hand must not be allowed to fall across the run; and be careful that your handkerchief does not drop out of your pocket on or near it. If a bunch of grass grows very tall and requires parting, part it with the end (not the handle) of your stick.”[8] The shape of the ear-flaps, which can be turned in different directions (Fig. 159), enables the rabbit to catch very slight sounds. The eyes are placed on the sides of the head, so that the animal has a wide field of view, and an enemy approaching from behind is not likely to be unnoticed. The eye of the rabbit is very similar in structure to our own, but it possesses one useful adjunct which ours has lost, in the shape of a third eyelid—an opaque flap of skin which lies in the inner angle, and can be drawn over the eyeball at [Pg 219] will. The little fleshy nodule in the corresponding position of the human eye is a rudiment of a similar structure.