This presents a large band, Fig. 30, straight, as in Fig. 43, and bounded on the sides by two parallel lines, as seen in the same figures, or by curved lines, as in Fig. 34. It sometimes rises scarcely a fourth part up the perineum, as in Fig. 38; at others, it reaches or passes beyond that part, forming a straight band, as in Figs. 35 and 43, or is folded into squares, as in Figs. 31 and 36, or truncated, Fig. 38, or terminated by one or several points, Figs. 32, 33, 41, 50. In some cows this band extends as far as the base of the vulva, Figs. 40 and 48; in others, it embraces more or less of the lower part of the vulva, Figs. 29, 30, 39, and 47. Milk-mirrors are sometimes symmetrical, as in Figs. 29, 30, 34, 35, 37, and 38; sometimes without symmetry, as in Figs. 42, 45, and 50. When there is a great difference in the extent of the two halves, it almost always happens that the teats on the side where the mirror is best developed give, as we shall see, more milk than those of the opposite side. We will remark here that the left half of the mirror is almost always the largest; and so, when the perinean part is folded into a square, it is on this side of the body that it unfolds, as in Figs. 31, 36, and 42. Of three thousand cows in Denmark, M. Andersen found only a single one whose escutcheon varied even a little from this rule. We have observed the contrary only in a single case, and that was on a bull. The perinean part of the mirror formed a band of an inch to an inch and a half in breadth, irregular, but situated, in great measure, on the right side of the body. Stretching towards the upper part of the perineum, it formed a kind of square, with a small projecting point on the right, Fig. 51. [Illustration: Fig. 33.] [Illustration: Fig. 34.] [Illustration: Fig. 35.] [Illustration: Fig. 36.] [Illustration: Fig. 37.] The mirrors having a value in proportion to the space they occupy, it is of great importance to attend to all the rows of down-growing hairs, which diminish its extent of surface, whether these tufts are in the midst of the mirror, Figs. 45, 46, and 47, or form indentations on its edges, as in Figs. 42, 44, 45, 46, and 48. These indentations, concealed in part by the folds of the skin, are sometimes seen with difficulty; but it is important to take them into account, since in a great many cows they materially lessen the size of the mirror. We often find cows whose milk-mirror at first sight appears very large, but which are only medium milkers; and it will usually be found that lateral indentations greatly diminish the surface of up-growing hair. Many errors are committed in estimating the value of such cows, from a want of attention to the real extent of the milk-mirror.