COKALLINES. 167 



(Gray), and Leiopafhes Lamarckii (Haime), were present on the same 

 coral, the Gerardia of Lamarck. It is thus recognized that, under 

 the general denomination of polyps, very distinct genera are found, 

 some being of the Hydra type, others belonging to the Plumularia. 

 The first are very common on our coast : they include the Tubularia, 

 the Campanularia, and the Sertularia. 



The Eeed Tubularia (T. indivisa) is remarkably curious : its 

 numerous stems are horny, yellow, and marked at intervals with 

 irregular knots, resembling the joints of a straw. Their lower ex- 

 tremity is tortuous, and apt to adhere to foreign bodies ; the upper 

 part is nearly upright, and slightly flexuous, the whole resembling 

 some flowering plant, without leaves or lateral branches. The 

 Campanularias are altogether different ; the end of the branches 

 whence the polyps issue are broad and bell-shaped, 0. dichotoma 

 presenting a stem of brownish colour, thin as a silken thread, but 

 strong and elastic. The polyps are numerous, a branch eight inches 

 in height being inhabited by as many as twelve hundred individuals. 



The Sertularias have a horny stem, sometimes simple, sometimes 

 branching, and may easily be mistaken for small plants. Their name 

 is derived from the Latin sertum, a bouquet ; and, indeed, they can 

 only be described as trees in miniature, with branches yellow and 

 semi-transparent, each tree having seven, eight, twelve, or twenty 

 small panicles, each of which will contain about five hundred animals, 

 the tree itself containing probably an association of ten thousand. 

 Occasionally Sertularia argentea is said to afford shelter and employ- 

 ment for a hundred thousand of these creatures. S.falcata, having 

 all the grace and elegance of the delicate and slender Mimosa, is now 

 placed among the Bryozoares. 



The minute cells in which the polyps are lodged are not always 

 arranged in the same manner. Sometimes the cells occupy one side 

 only; in other instances they occupy both; sometimes they are 

 grouped like the pipes of an organ, at others they are ranged spirally 

 round the stem, or arranged at intervals, forming horizontal rings 

 round it. 



The Aleyonaria are very common on some parts of our coast, where 

 scarcely a stone or shell is dredged up that does not support one or 

 more specimens known to the fishermen as " cow's paps,*' " dead men's 

 fingers," and other popular names. This round and lobed fleshy mass 



