The young Lobster when first hatched (Fig. 8) differs considerably in general appearance from the adult animal. The abdominal somites have a row of spines down the middle of the back, and the telson has a forked shape. There are no swimmerets, but, as already mentioned, the legs bear large exopodites, which are used like oars, and by means of these the larval Lobster swims about at the surface of the sea. The claws or chelæ are at first hardly larger than the other legs, but later they increase in size, the swimmerets are developed, the exopodites of the legs are lost, and the young Lobster, sinking to the bottom of the sea, takes on the creeping habits and gradually assumes the shape of the adult. In many Crustacea the changes of shape or metamorphoses undergone after hatching are much greater than in the Lobster. Some of these changes and their probable significance will be considered at greater length in a later chapter. The two large claws of the Lobster (see Plate I.) are not quite alike in size or in shape. The smaller of the two has the inner edges of the fingers sharp and set with saw-like teeth; the larger has the fingers armed with blunt rounded knobs. The larger claw is adapted for crushing the shells of the animals on which the Lobster feeds, while the smaller serves for holding and tearing the prey. In the Lobster, as in many of the higher Crustacea in which this asymmetry occurs, the larger claw may be indifferently on either side of the body. There are certain cases, however, among Crabs where the large claw is constantly on the same side of the body, or, in other words, all the individuals are either right-handed or, more rarely, left-handed.