It is evident that the outer envelope of the gonophore represents the ex-umbral ectoderm (ex.), and that the inner ectoderm lining the cavity represents the sub-umbral ectoderm of the free medusa.
The sub-umbral cavity (s.c.) functions as a brood-space for the developing embryos, which are set free by rupture of the wall.
` tion of the coelenteric 1 V cavity; in the second stage the tentacles Much modified from C. Chun, " Coelenterata," in grow out as secondary Bronn's Tierreich.
The entocodon, however developed, gives rise at first to a closed cavity, representing a closing over of the umbrella, temporary in the bud destined to be a free medusa, but usually permanent in the sessile gonophore.
45, C, ed.) may be formed over all, as in Garveia, &c.; or the entocodon may remain solid and without cavity until after the formation of the manubrium, or may never acquire a cavity at all, as described above for the gonophores.