Page:The aquarium - an unveiling of the wonders of the deep sea.djvu/136

Rh infolds the margin to so great an extent as nearly to conceal the tentacles. The footstalk is also contracted by corrugation, but no sooner is it immersed again than this is lengthened, and the tentacles are expanded as before. The changes in the outline of the lips, and slight jerkings of the body to and fro, or corrugations of the surface in various degrees, constitute the chief of its movements.

On cutting off the globular head of a tentacle and submitting it to pressure, I found the structure to contain a moderate number of minute thread-capsules, about th of an inch in length, of two forms:—the one long-oval, apparently carrying a simple thread, the other oval, with a distinct internal chamber near one end, indicating an armature on the thread. The threads were projected from the former in several instances, but I saw no example of the propulsion of the latter.

I afterwards obtained a second specimen of this little Lucernaria, on a similar rocky ledge which runs out from the eastern point of Lulworth Cove. In every respect it agreed with the one above described, which may therefore be considered as representing its normal condition. Though inconspicuous for size or colour, it is a form of much interest to the naturalist, as it is evidently much less aberrant from the Actinæ proper, with which its affinities connect it, than the broad gelatinous-disked species to which the genus Lucernaria was confined before the discovery of L. cyathiformis. Though still peculiar, the form is not very remote from that of the genus Corynactis, by which, as I conceive, it is linked with Actinia.