Page:Hardwicke's Science-Gossip - Volume 1.pdf/301

Sea-Anemones.—I should like English aquarium-keepers to know of the enormous dimensions attained by some English sea-anemones in Germany, that is in the Hamburg aquarium. About a year ago I received from Torquay three specimens of the Opelet (Anthea cereus), each measuring about two inches in diameter in their state of greatest expansion; but by constantly feeding them, increasing the quantity of food as they grew bigger, they have become ten inches in diameter when fully out, and they are from four to five inches in diameter of column. Their tentacles are very strong, so that their tug will bend a cane four feet long in the act of pulling it away from them. Every day each of them eats one large oyster or mussel, or, when I have neither of those mollusks, I give each a quarter of an ounce of raw beefsteak, free from fat. Of this food I never see one particle after the animal has fairly swallowed it. These Antheas can sting very severely. I once drew one of their tentacles across my tongue, and the pain and the swelling produced were great, lasting several hours. I do not know whether this species has been observed of such large dimensions in the sea as I have named: if not, it would seem that by constant attention and feeding, some of the lowest animals (as well as many of the higher creatures) can be improved in a state of captivity. I may mention that they are in a tank measuring 72 inches long, 60 inches broad, and 30 inches high, containing about 300 gallons of sea-water, and that from 300 to 500 gallons—according to weather—run through the tank day and night, every twenty-four hours. I am very successful also with the great "Thick-horned Sea-anemone" (Tealia crassicornis), and in a tank of the same size and stream power as that just named, I have not less than eighty of these Crassicornis, most of them finely coloured and marked, and many of them being monsters of six, seven, and eight inches diameter when quite expanded. Each of these takes its mussel or oyster daily, or more rarely its piece of steak, and as with Anthea, not a morsel is rejected. The other anemones under my care, consisting of Bunodes Ballii, B. gemmacea, and B. thallia; and Sagartia viduata, S. troglodyes, S. nivea, S. venusta, S. bellis, and many others, take food with surprising readiness and in great quantities, so long as I feed them regularly, and carefully give each individual its proper quantity with a pair of wooden forceps. In this way I pass about three hours every day in feeding the Anemones and Madrepores only. But if I neglect the feeding, the creatures rapidly deteriorate in size and vigour, and lose their power of taking food. Of course if the streams of sea-water ever ceased passing through the tanks, the whole thing would speedily come to grief, from the water becoming fouled by the introduction of such a great quantity of oysters, mussels, and beef every day; but as it is, it remains perfectly transparent. I have mentioned twice that when the food has disappeared in the anemone's stomach, I never perceive any of it afterwards in the form of excrement, but only in the shape of cast-off epidermal matter, which falls in rings of dirty-looking mucus around the exterior of the bases of the anemones, and those which take most food cast off the largest quantity of skin. I omitted to state in its proper place in this little communication, that if I were to name the dimensions of some of our Sagartia venusta, Bunodes Ballii, and Corynactis viridis, which have been purposely fed up to ascertain how big they will grow, I should be accused of exaggeration. Actinoloba dianthus feeds well with me, and attains a good size; but I have never seen one so large as a specimen I got from Weymouth in the summer of 1857; it stood twenty inches high, measured ten inches across the disk, and the column varied from five to three inches in diameter.—W. Alford Lloyd, Zoological Gardens, Hamburg.

Cretaceous Fossils.—Your correspondent A. G. R. (see p. 229) criticises Page, forgetting that he himself is in the wrong. For though Pecten and Spondylus, &c., have fossil representatives, yet no living species of either genus "is exactly similar to those in a fossil state in the chalk." A. G. R. should familiarize himself with the principles of classification; the mutual relations of species of a genus. Distinctive characters can be pointed out between any chalk-Pecten and any living one. Pertea should be Pecten; Plagiostoma is synonymous with Lima, but Spondylus is evidently the genus meant. Turbitella is a new name; Turritella and Terebratula are chalk genera; probably the latter is intended.—Ralph Tate, F.G.S.

Coral Reefs.—In this paper (see p. 221) the author parallels several coral-bearing formations with coral reefs of the present day. None of the really indicate the physical conditions at present prevailing in existing tropical seas. The only limestone that at all approaches to the structures at present in process of formation, is the Coral Limestone in the district of Trichinopoly, East India. This limestone rests on gneiss, and appears as ridges, extending from a few hundred yards to three and four miles in length. Its chemical and physical characters correspond to those of recent coral reef rock. These ancient coral reefs are surrounded by strata of the Ootatoor and Trichinopoly groups of the Cretaceous epoch; and evidences are not wanting to show that this coral limestone was formed on a sinking base, around which were deposited contemporaneously the Ootatoor and Trichinopoly beds.—For Mr. Sarby read Mr. Sorby; for Mattheim read Nattheim.—Ralph Tate, F.G.S.