. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. OVUM. 15 testine, and anus, and moves actively through the water. Sars who had observed this body in 1835, was the first to suggest in 1844 that it might be the early condition of a star-fish*, and this view was confirmed by the admirable researches of J. Miiller f, and by observations of Koren and DanielsonJ, who have shown that the Asterias is gradually formed out of a small granular mass which surrounds the stomach of the Bipinnaria, and becomes se- parated from the stock when in a compara- tively early state of advan
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. OVUM. 15 testine, and anus, and moves actively through the water. Sars who had observed this body in 1835, was the first to suggest in 1844 that it might be the early condition of a star-fish*, and this view was confirmed by the admirable researches of J. Miiller f, and by observations of Koren and DanielsonJ, who have shown that the Asterias is gradually formed out of a small granular mass which surrounds the stomach of the Bipinnaria, and becomes se- parated from the stock when in a compara- tively early state of advancement. The larva stock moves about afterwards for a few days, Fig. Pluteus puradoxus {from Midler). A, Fluteus before the commencement of the formation of the Ophiura. u, Ophiura formed on the side of the gullet. * Wiegmann's Archiv. 1844, part i. p. 176. f Mem. of the Berlin Acad. 1846 and 1848. 1 Ann. des Sc. Nat. 1847, p. 348. and then appears to die without giving rise to any farther progeny. The gemmiparous larva of some other kinds of the Echinodermata was first described by J. Miiller as a distinct animal, under the name of Pluteus, before he was acquainted with the phenomena of its subsequent de- velopment: in 1846 he traced the relation between one kind of this body which he had called Pluteus paradoxus, and the Ophiura, and between another kind of Pluteus and Echinus, ascertaining it to be the same that has just been stated to exist between the Bipinnaria and the Asterias. The Plntens presents the form of a quadrangular pyramidal frame, with four large ciliated limbs at the angles, and four smaller ones suspended from the middle below, while the upper part is surmounted by ;i sort of dome. It bears some resemblance to a Beroe, and might be de- scribed as the ciliograde larva of an Echino- clerm. The form differs, however, somewhat for various species of Ophiura and Echinus. In the centre of the dome and round the mouth of the Pluteus a granular mass is de- scrib
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