The actinix apparently transport themselves to any considerable distance from their abode, by detaching the base, the under part of which is kept inflated, and they are thus carried by the waves in a reversed position. But, independent of this, their adhesion to rocks, stones, or other substances, is so powerful, that we have found no method of detaching them without injury, but violent and continued agitation of the water, an expedient which naturalists seem hitherto to have overlooked.
The generation of the actinix is not clearly ascertain ed. They appear to be hermaphrodites, and to propagate without the sexual union. The number of young is various, from one to at least twenty, which arc produced by the mouth. The abbe Dicquemare had studied these creatures ten years before discovering this fact ; but it •was observed long before by Ellis. The period of pro pagation, in a state of confinement, is not limited to any particular season. It commonly takes place in autumn, which seems consistent with what probably succeeds in a state of nature. The young, according to our obser vations, have only one row of tentacula, few in number, though the parent had three ; whence the last are gra dually acquired ; for we have seen those which have sixty or eighty, when full grown, produce a young actinia with only four : thus resembling certain terrestrial ani mals, which acquire additional legs always as they grow older.
The actinia also propagate by spontaneous division, it is said, and the divided part becomes a perfect ani mal. When the period of this phenomenon approaches, it appears restless and disturbed ; various extensions, contractions, and contortions of the body ensue, amidst which, several fragments separate from the lower part towards the base. These, though at first rude and shapeless, are gradually unfolded into new actinix, with all the parts and proportions of the old ones. We have not witnessed this mode of propagation, it is true, and perhaps it but rarely happens. We know, however, that there is a species of planaria, common in Scotland, which propagates in a manner analogous. The tail se parates from the body : it remains contracted, and almost motionless. Should the temperature of the atmosphere be favourable, a new head shoots forth from the upper extremity, similar, in all respects, to that of the parent animal ; while, in the meantime, the parent, whose acti vity and motion have hardly undergone any sensible in terruption, acquires a new tail. Under the article
DIALCULE, we shall also quote some surprising instances of propagation, by spontaneous division.
But, independent of the natural modes of generation, the animal flower enjoys the property of reproducing the parts losf or destroyed, in an astonishing degree. Not only are full and perfect actinix produced, by divi sion into two, or more, portions, with the knife ; but, on tearing these from the place of adhesion, the very shreds, or fragments, left of the base, regenerate into complete animals, with all the members peculiar to their species.
The great extent of this remarkable prerogatiVe, was first observed by the able Dicquemare of Havre de Grace, to whom we are indebted for ample details of its progress anti operation. On the 12th of July, he cut asunder an actinia towards the base. It continued ad hering to the side of the vessel containing it, and was in motion during several days. Then, having detached it self, it fixed in another place, where it remained station ary. On the 27th it again began to move, and preserved some motion until the end of August, when it became soft and icetid, and apparently dead. Fresh sea water was supplied however ; and in November its motion was perceptibly resumed. On the 28th it climbed up to the top of the vessel ; the rudiments of new tenta cula were then visible. This animal perished by an ac cident, after having survived the operation fourteen months.
Another actinia was cut asunder on the 9th of Novem ber :—the basis immediately contracted, and remained in the same state until the 113th of January, when it shifted its position. So early as the 15th, two rows of new tentacula were visible, and the animal was in mo tion. It then fed on musOes, and the reproduced parts were soon nearly as large as those cut off. The upper portion seized, and swallowed, part of a muscle, after the operation, which passed through and through the opening, for want of a base. This fact may perhaps be considered further evidence, that many animals are not so exquisitely sensible of pain as others. For, in addi tion to it, we have authentic narratives of some animals, which have survived incredibly long, though deprived of the heart and the brain : of decapitated butterflies sport ing among the flowers, and mangled insects living near ly as long as those that were entire.