inula's Usage Examples:

hyp, The epidermic cell-layer (so-called hypodermis), the cells of which increase in volume below each lens, 1, and become nerve-end cells or retinula-cells, rt; in A, the letters rh point to a rhabdomere secreted by the cell rt; c, the peculiar central spherical cell; n, nerve fibres; mes, mesoblastic skeletal tissue; ch, chitinous cuticle.

Brooks, on the other hand, as stated above, regards the medusa as the older type and looks upon both polyp and medusa, in the Hydromedusae, as derived from a free-swimming or floating actinula, the polyp being thus merely a fixed nutritive stage, possessing secondarily acquired powers of multiplication by budding.

A finch (Nesospiza acunhae), a thrush (Nesocichla eremita), and a water-hen (Gallinula nesiotis) are the only land birds - the first two being peculiar to the islands.

without a hydroid phase; the medusa develops directly from the actinula larva, which may, however, multiply by budding.

23, article Arachnida) a single retinula or group of nerve-end-cells is grouped beneath each associated lens.

The later eyes are polymeniscous, with specialized vitrellae and retinulae of a definite type peculiar to this grade.

Those nearest to the lens are the corneagen cells of this more elaborated eye, and those between the original retinula cells and the corneagen cells become firm and transparent.

If the embryo is set free as a free-swimming, so-called planula-larva, in the blastula, parenchymula, or gastrula stage, then a free actinula stage is not found; if, on the other hand, a free actinula occurs, then there is no free planula stage.

In those Euthyneura in which the shell is entirely absent in the adult, it is, except in the three genera Cenia, Runcina and Vaginula, developed in the larva and then falls off.

26) a tendency to group themselves into " retinulae," consisting of five to twelve cells united by vertical deposits of chitin (rhabdoms).

The ectoderm loses entirely the ciliation which it had in the planula and actinula stages and commonly secretes on its external surface a protective or supporting investment, the perisarc.