432 POLYPI. 
A. senilis, L.* Three inches wide, with a coriaceous, uneven, 
orange-coloured envelope, and two ranges of moderately long 
tentacula, marked with a rosy ring. It is generally found on 
the sand, into which it soon sinks if disturbed. 
A. equina, L.t The skin soft and finely striated, usually of 
a fine purple colour frequently spotted with green; it is smaller 
than the senilis, with longer and more numerous tentacula. 
This species covers all the rocks on the French coast of the 
British channel, ornamenting them as if with the most splendid 
flowers. 
A. plumosa, Cuv.{ White, and more than four inches wide; 
the edges of its mouth are expanded into lobes, all loaded with 
innumerable little tentacula; there is an inner range of larger 
ones. 
_ A. effeta; Rond., lib., XVII, cap. xvill; Bast. xiv, 2§. A 
light-brown, longitudinally streaked with whitish; its form is 
usually elongated and frequently narrowest below; skin smooth ; 
tentacula numerous. When it contracts, long filaments arising 
from the ovaries are frequently protruded through the mouth. 
It usually fixes itself on shells, and is extremely common in 
the Mediterranean ||. 
The Tuarasstanrua, Ruppel, are Actiniz with ramified ten- 
tacula ¥. 
The Discosoma, Rupp., are Actinizin which the tentacula are al- 
most reduced to nothing by their shortness **. 
ZoaNTHus, Cur, 
The same fleshy tissue and arrangement of the mouth and tenta- 
cula as in the Actiniz,and a nearly similar organization; but these 
* It is the Actinia senilis, Gm., Diquemare, Phil. Trans., LXIII, pl. xvi. f. 10, 
and pl. xvii, f. 11; the Actinia crassicornis, Baster, XIII, 1; the Act. digitata, Zool. 
Dan., CXXXIII; and the Act. holsatica, lb., CXXXIX. 
+ It is the Actinia equina, L., Diquem., Philos. Trans., LXIII, xvi, 1, 2,3, and 
the Hydra mesembrianthemum, Gm., Geert., Phil., Trans. LII, 1—5. 
+ We have no good figure of this species, but I think that of Baster, XIII, 2, 
must represent it. The Hydra dianthus, Gm., Ellis, Phil. Trans., LVII, xix, 8, and 
Encye., LXXI, 5, is also closely allied to it, and perhaps even the Hydra anemone, 
Phil. Trans., [b., 4, 5, Encyc., Ib., 5, 6. 
§ I also believe it to be the Act. felina, Diquem., Phil. Trans., LXIII, xvi, 13, 
referred by Gmelin to his Actinia truncata. 
It is necessary to remark, that the variation in the form and colours of the Actiniz 
renders them extremely difficult to determine, and that we are not to trust to the 
characters established by observers, and still less to the approximations proposed by 
compilers. 
|| Add of nearly certain species, Hydra cereus,Gm.; Gzert., Phil. Trans. L1I, i, 1; 
Encyc., LXXIITI, 1, 2;—Hydra bellis, Phil. Trans. Ib., 2; Encye. Ib. 4;—Hydra 
helianthus, Ellis, Phil. Trans., LVII, xix, 6,7: Encye., LXXI, 1, 2;— Hydra aster, 
Ellis., Phil. Trans., LVII, xix,3; Encye. LXXI, 3 ;—Actinia varians, Zool. Dan., 
CXXIX ;—Acet. candida, Ib., CXV ;—Act. plumosa, Ib., LXX XVIII ;—Act. coccinea, 
Ib., LXIII, 1, 3 ;—Act. viridis, Forsk., XXVII, B; Act. rubra, Brug.; Forsk., Ib., 
A ;—Aet. maculata, Brug. ; Forsk., 1b., C ;—Actinia quadricolor, Ruppel, Voy., Moll., 
pli; f. 3, &c. 
q Thal. aster, Ruppel, Moll., pl. i, f. 2. 
** Disc. nummiforme, Id, Ib., f. 1. 
