2671. In the circulation the whole organism, or intestine, lung and integument, is combined. It is therefore the fundamental system, which includes the whole mass of the body.
b. FUNCTIONS OF THE ANIMAL SYSTEMS.
1. Of the Osseous System.
2672. The functions of the osseous system are simply mechanical relations, such as solidity, form and motion.
2673. The motion of the joints presents to our notice interesting relations, especially in reference to the motion of the vertebræ, ribs, limbs and jaws upon each other, but these could not be here treated of in detail.
2674. The acts of swimming, creeping, standing, walking, running, leaping, climbing, and flying, do not exhibit simply mechanical, but truly philosophical moments.
a. Bodily Motion.
2675. Swimming can take place through simple contraction of the body, without locomotive members. It is the continuation of the vesicle's first process of origination; as in the Infusoria and Polyps. In the Worms and Serpents it is effected by an undulating motion of the body, whereby the water is struck with oblique surfaces; there it is fibrous motion. In the Holothuriæ and many aquatic larvæ, it is a propulsion, effected by expelling water from the anus, and thus by squirts, there being consequently contraction of the body or arteriose straitening of the sphincter muscles. In Fishes, swimming is a rowing or remigial stroke, produced by lever-motion, together with the oblique slap made by their tail.
2676. Creeping is either a shortening of the body by fibrous motion, as in the Snails, or an undulatory motion, as in the Serpents.
b. Pedal Motion.