Page 286 - Third Book of Reading Lessons

READING LESSONS. 285
pact nature than in the higher orders of animals. The skeleton may be divided into ur chief parts; the vertebral column, the head, the respiratory appa­ ratus, and the limbs. The vertebral column consists of vertebr , which are concave at each end and pierced in the middle; and when joined together, the hollow place between each two is occupied by a glutinous substance, which passes om one space to
the next, through the hole in each bone.
6. The teeth in shes are almost entirely osseous; they are usually of a simple, spine-like rm, and re­ curved at the tip. Teeth are und in almost every bone in the interior of the mouth.
7. As regards the senses, those of taste and touch appear to be but slightly developed in shes. vVhen we nd the tongue thickly covered with teeth, as js o en the case, and used as an organ of prehension ; and when_we consider the quick manner in which the od is swallowed, it would certainly appear that their sense of taste is very slight.
8. The eyes are di erently placed in the various species of shes, in accordance with their habits; r the most part they are placed laterally, or side-wise, and in some, as those that Iive at the bottom of the water, we nd them directed upwards.
9. The sight of shes is acute ; the range_ of vision, however, is probably somewhat limited. The eyes, which are rnished with a spherical lens, are gener­ ally large; but in some species they are very small, whilst others appear to be destitute of them.
10. Although shes appear not to possess certain portions of the auditory apparatus observed in ani­ mals of a higher grade, they, nevertheless, possess the sense of hearing.
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