. The Canadian naturalist and quarterly journal of science. Natural history -- Periodicals. 418 THE CANADIAN NATURALIST. [DeC. Agassiz Rhodiictinia Davisii, and which is tlie most common species on the north shore of the Gulf and River St. Lawrence, may be noticed here. It is probably a variety of Actinia crassi- cor?u's of the British coast. Externally, when expanded, it pre- sents a cylindrical body attached at the lower extremity to a rock or stone, and at the upper having a crown of thick worm-like ten- tacles arranged in several rows, in the centre of which is the mouth. The external surf
. The Canadian naturalist and quarterly journal of science. Natural history -- Periodicals. 418 THE CANADIAN NATURALIST. [DeC. Agassiz Rhodiictinia Davisii, and which is tlie most common species on the north shore of the Gulf and River St. Lawrence, may be noticed here. It is probably a variety of Actinia crassi- cor?u's of the British coast. Externally, when expanded, it pre- sents a cylindrical body attached at the lower extremity to a rock or stone, and at the upper having a crown of thick worm-like ten- tacles arranged in several rows, in the centre of which is the mouth. The external surface of the body, the tentacles and disc are often gaily coloured in shades of purple, crimson, and flesh colour, though diff"erent individuals differ very much among them- selves in this respect, and also in the smoothness or tuberculated character of the body. When fully expanded, the animal has the appearance of an aster or other stellate flower. When irritated or alarmed it withdraws its tentacles, contracts the body wall over the disc, and assumes the form of a flattened cone. Its food con- sists of such small animals as may be attracted by its gay colours, or may accidentally come within reach of its tentacles. Tu enable it to seize these it has in the substance of the tentacles an appa- ratus of extensile and retractile thread-cells, by means of which it can hold with some tenacity any object which touches the ten- tacles, and can also exert a benumbing influence tending to para- lyze and subdue the resistance of its prey. The specimens figured (Figs. 43 and 47,) were dredged in Gasp^, and referred to a new species, R. nitida, but may possibly be a variety of the above.— Another variety, found in the River St. Lawrence, is permanently tuberculated, and cannot be distinguished from A. (Urtichiia') crassicornis, as ordinarily seen in Great liritain. Fig. 47. Actinia (Urtidula) , contrat'ted, and suuiller individual expanded. A larger and often more beaut
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