432 



POLYPI. 



A. senilis, L.* Three inches wide, with a coriaceous, uneven, 

 orange-coloured envelope, and two ranges of naoderately long 

 tentacula, marked with a rosy ring. It is generally found on 

 the sand, into which it soon sinks if disturbed. 



A. equina, L.f The skin soft and finely striated, usually of 

 a fine purple colour frequently s^^otted with green ; it is smaller 

 tlian 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. effceta; Rond., lib., XVII, cap. xviii; 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 Thal.\ssiantha, Ruppel, are Actini?e with ramified ten- 

 tacula^. 

 The DiscosoMA, Rupp., are Actiniae in which the tentacula are al- 

 most reduced to nothing by their shortness**. 



ZoANTHus, Cuv, 

 The same fleshy tissue and arrangement of the mouth and tenta- 

 cula as in the Actiniae, and a nearly similar organization; but these 



* It is the Actinia senilis, Gm., Diquemare, Phil. Trans., LXIII, pi. xvi. f. 10, 

 and pi. xvii, f. 11; the Actinia crassicornis, Baster, XIII, 1; the Act. diyitata, Zool. 

 Dan., CXXXIII ; and the Act. hokatica, lb., CXXXIX. 



-|- It is the Actinia equina, L., Diquem., Philos. Trans., LXIII, xvi, 1, 2, 3, and 

 the Hydra mesemhrianthemum, Gm., G«rt., Phil., Trans. LII. 1 — 5. 



X We have no good figure of this species, but I think that of Baster, XIII, 2, 

 must represent it. The Hydra dianthus, Gm., Elli>-, Phil. Trans., LVII, xix, 8, and 

 Encyc., LXXI, 5, is also closely allied to it, and perhaps even the Hydra anemone, 

 Phil. Trans., lb., 4, 5, Encyc, lb., 5, 6. 



§ I also believe it to be the .4c/. felina, Diquem., Phi). 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 Actiniae 

 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. 



II Add of nearly certain species, Hydra cereus, Gm. ; Gtert., Phil. Trans. LII, i, 1 ; 

 Encyc, LXXIII, 1, -i;— Hydra bellis, Phil. Trans. lb., 2; Encyc Ih. -i ;— Hydra 

 helianthus, Ellis, Phil. Trans., LVII, xix, 6, 7 : Encyc, LXXI, 1, 2 ; — Hydra aster, 

 Ellis., Phil. Trans., LVII, xix, 3 ; Encyc. LXXI, 3 ; — Actinia rarians, Zool. Dan., 

 CXXIX ■,—Act. Candida, lb., Q,X\;—Act. j)lumosa, lb., LXXXVIII ;—Act. coccinca, 

 lb., LXIII, 1, 3 ■,—Act. viridis, Forsk., XXVII, B ; Act. rubra, Brug. ; Forsk., lb., 

 A ; — Act. maculata, Brug. ; Forsk., lb., C ; — Actinia quadricolor, Ruppel, Voy., Moll., 

 pi. i, f. 3, &c 



If Thai, aster, Ruppel, Moll., pi. i, f, 2. 



** Disc.nummiforme, Id. lb., f. 1. 



