. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 58 POLYPIFERA. to consist of a transparent sac, in which are contained generally from four to six of the gemmules, which, as soon as the sac is torn, escape, and swim about with the greatest ac- tivity, affording a most interesting subject for microscopic investigation. When viewed with a power of 40, linear measure, they are seen to be of an oval or rounded form (Jig. 63, b), convex above and Fig. Halodactylus diaphanus, a gemmule seen from above; the cilia as when slowly acting round the margin in waves. (After Fa
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 58 POLYPIFERA. to consist of a transparent sac, in which are contained generally from four to six of the gemmules, which, as soon as the sac is torn, escape, and swim about with the greatest ac- tivity, affording a most interesting subject for microscopic investigation. When viewed with a power of 40, linear measure, they are seen to be of an oval or rounded form (Jig. 63, b), convex above and Fig. Halodactylus diaphanus, a gemmule seen from above; the cilia as when slowly acting round the margin in waves. (After Farre.) nearly plane below, and fringed at the margin with a single row of cilia, which appear to vibrate in succession around the whole cir- cumference. Under an amplification of 120 they assume a different aspect (fig. 64), and their minute structure is clearly discerned. Viewed as opaque objects, both the body and cilia have a silvery whiteness, but by transmitted light the former appears of a dark brown, and the cilia of a golden yellow colour. Upon the most convex part of the body, which is not generally in the centre, but leaning to one side, are set from three to five transparent bosses, surrounded by a circle, and other circles are seen extending to the base of the body, which is bounded by a row of promi- nent tubercles. These marginal tubercles are from thirty to forty in number; and from the circumstance of the cilia arising from them, Dr. Farre considers it probable that they are for the purpose of governing their motions, and therefore analogous to the muscular lobes of Hydatina senta and other Rotifera figured by Ehrenberg. No structure, however, could be detected in these, nor in any other part of the body, beyond a mere granular parenchyma. When thus highly magnified, it is seen that what examined with a lower power appeared to be a single cilinm is, in fact, a wave of cilia, and that their motion, instead of being in the direction of the circumference of the dis
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