Page 229 - Third Book of Reading Lessons

228 THIRD BOOK OF
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1. THE mammalia are placed at the head of the animal kingdom, not only because it is the class to which we ourselves belong, but also because all the species included in it enjoy the most numerous facul­ ties, the most delicate sensations, and the most varied powers of motion.
2. As the quantity of respiration in_ the mammalia · is moderate, so, generally speaking, these animals are rmed r walking on the earth, but, at the same time, with great rce and permanence of exertion.
., To this end, all the articulations of their ame have strictly de ned con rmations, which determine all their motions with rigorous precision. Some, how­ ever, can raise themselves in e air by means of · limbs considerably elongated, and connected by ex­ tensible membranes. Others, again, have their limbs so much shortened that they can move with cility in the water only; but these circumstances by no means deprive them of the essential characters of the class to which they belong.
3. The most essential di erences of the mammalia among themselves are, rst, in the organs of ouch, on which the dexterity of the animal mainly depends; and seconly, in those of mastication, which deter­ mine the nature of the aliment proper to every spe­ cies. On these essential characters is unded the division of the mammalia into orders. Everything relating to the digestive nctions is closely connect­ ed with these characters. The degree of perfection of the organs of touch may be estimated according to the number and moveableness of t e ngers, and
according to the greater or less proportion of- depth in which their extremity is enclosed in the claw or hoof. A hoof which completely envelops that part
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