The ring-canal is drawn out in Narcomedusae into festoons corresponding with the lobes of the margin, and may be obliterated altogether (Solmaris).
In this order the radial canals are represented only by wide gastric pouches, and in the family Solmaridae are suppressed altogether, so that the tentacles and the festoons of the ring-canal arise directly from the stomach.
As a result of this extension of the umbrellar margin, all structures belonging to this region, namely, the ring-canal, the nerve-rings, and the rim of thickened ectoderm, do not run an even course, but are thrown into festoons, caught up under the insertion of each tentacle in such a way that the ring-canal and its accompaniments form in each notch of the umbrellar margin an inverted V, the apex of which corresponds to the insertion of the tentacle; in some cases the limbs of the V may run for some distance parallel to one another, and may be fused into one, giving a figure better compared to an inverted Y.
The country in general is a fern paradise, and the iridescent creeping Selaginella (akin to Lycopodium) festoons the undergrowth by the wayside.
Besides the three chief regions into which the mainland is thus seen to be divided, attention should be drawn to the festoons of islands which border the eastern side of the continent, and which are undoubtedly due to causes similar to those which produced the folds of the folded belt.
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