. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 558 MYRIAPODA. segments, inclosed in their proper skin, were now more elongated and very much en- larged, and the new segments were further developed as well as the germinal membrane. The external tegument was more extensively separated from the whole body, especially at the posterior part, and the head was retracted within it and bent on the under part of the thorax. It was thus evident that this tegu- ment was not of recent formation, that it simply enclosed the animal as the whole had been previously enclosed in the a
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 558 MYRIAPODA. segments, inclosed in their proper skin, were now more elongated and very much en- larged, and the new segments were further developed as well as the germinal membrane. The external tegument was more extensively separated from the whole body, especially at the posterior part, and the head was retracted within it and bent on the under part of the thorax. It was thus evident that this tegu- ment was not of recent formation, that it simply enclosed the animal as the whole had been previously enclosed in the amnion, as is proved by the circumstance that it extended smoothly over the whole body, antennae and legs, and did not follow the inflection or redu- plication of the proper surface of the animal like the true skin beneath it, but passed di- rectly over the segments, and was simply pro- truded or distended by the growth of parts be- neath, as in the instance of the new legs (6). Up to this period, therefore, observes Mr. New- port, the young Jnlus must still be regarded as in the embryo condition, although for a day or two after bursting the amnion, it possessed the power of locomotion and evinced some developement of instinct. At its next change of skin, when it enters what Mr. Newport regards as the fourth period of its developement, and when it has acquired fourteen pairs of legs, it assumes for the first time a condition analogous to the larva state of true insects on bursting from the ovum; the difference be- tween the two being that the analogue of this tegument of the embryo in insects is slipped off at the bursting of the amnion on leaving the shell, while that of the Myriapod is not thrown off until some days after it has entirely left the ovum. This embryo condition of the animal will therefore explain the circumstance of its first acquiring a slight power of locomotion, and then remaining perfectly quiescent without taking food to prepare for this change—the third
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