| OCR Text |
Show 248 LIEUT. DE CRESPIGNY ON THE HABITS OF AN ACTINIA. [Apr. 8, the white tip to the tail and the size, the Ardennes variety being a much larger and stronger animal. Nilsson describes a variety very like the Vulpes melanogaster as inhabiting Scandinavia. 10. Notes on the Friendship existing between the Malacopte-rygian Fish Premnas biaculeatus and the Actinia crassi-cornis. By Lieut. C. C. D E C R E S P I G N Y *. The A^nemone here spoken of is found at Labuan in various habitats- sometimes domiciled in rows along the horizontal fissures of sandstone rocks (the positions being chosen so that at low water they may be just awash), in other cases surrounding and covering a mass of exposed dead madrepore. It is also found attached to rocks or dead coral some inches under the surface of the sand, and from this vantage ground protruding or withdrawing its tentacula at pleasure, so that when they are withdrawn the animal is no longer visible. On a calm evening, when the tide is out, one may observe with advantage the sympathy which appears to exist between this animal and the little fish called Premnas biaculeatus. The Actinia is in a state of quiescence, allowing its tentacula to float and move about freely in obedience to the impulse of each ripple of the water, they being now supple, pointed at the extremities, and gravitating downwards. A Premnas now passes over the Anemone, and immediately the tentacula become erect and diverge as if galvanized, while their extremities become clubby and phosphorescent. The fish hovers over it, gently rubbing the tentacula with his pectoral fins, and so will remain for some time. The hand-net is passed quietly down under the Anemone, and the alarmed fish, instead of swimming away, dives into the body of its friend, the tentacles closing over it and thus burying it in a living tomb. The hand of the captor now disturbs the fish in its hidden retreat, and upon its again rushing forth from its hiding-place the net is drawn to the surface of the water and the little fellow captured. The natural colour of this fish is pale red, having three perpendicular white stripes on the body. Upon its attaining full growth, however, when it is from four to five inches long, it becomes almost black, and the stripes are very nearly obliterated. In captivity I have known an Anemone live in perfect harmony with a Premnas for nearly a year. One morning the fish was found dead outside its tub, from which it had leapt in the night; the Anemone sickened, became elongated and flaccid, and died in a few days. On the other hand, I have known a fish live in a tub for a long time without the society of its complementary Anemone. It may be that the fish spawns upon the Anemone, or that by continually rubbing its fins against the extremities of the tentacles it rids itself and its friend of disagreeable parasites, or that it causes a continuous flow of water across the body of its friend, in which stream are conveyed the animalcula on which it lives. * Communicated hy E. Iliggins, Esq., F.Z.S. |
