Besides the sphincter pupillae, the fibres of the ciliary muscle are stimulated.
During this time the illusion of a wheel or wheels produced by the ciliary action of the disk had puzzled all observers.
Its stimulant action on the iris and ciliary muscle is employed when they are weak or paralysed.
The cirri or tentacles, of which three or four pairs are present, are capable of being protruded, and the minute larva swims by means of the ciliary action they produce.
This thread gives rise to a spiral ciliated band lying in a depression on the body of each spermatozoid; the large spermatozoids eventually escape from the pollen-tube, and are able to perform ciliary movements in the watery liquid which occurs between the thin papery remnant of nucellar tissue and the archegonial necks.
In a few genera the place of the chitinoid coat is taken by a ciliary investment and in most families the structure of the layers is characteristic.
Such ciliary motion is known in the adult condition of the cells of Volvocaceae, but where this is not the case the reproductive cells are endowed with motility for a brief period.
Preserves are used to conceal deformities or to protect the eyes in the many conditions where they cannot tolerate bright light, such as ulceration and inflammation of the cornea, certain diseases of the iris, ciliary body, choroid, and retina.
In the Ostrea edulis fertilization of the eggs is effected at the moment of their escape from the uro - genital groove, or even before, by means of spermatozoa drawn into the sub-pallial chamber by the incurrent ciliary stream, and the embryos pass through the early stages of development whilst entangled between the gill-lamellae of the female parent (fig.