434 POLYPI. 



in the cavity of their body. They are sensible to the action of light, 

 and seek it, but their most wonderful property is that of being con- 

 stantly reproduced by the indefinite excision of their parts, so that 

 we can multiply them at will by means of division. Their natural 

 increase is by shoots which push out from various points of the body 

 of the adult, and at first resemble branches. 



Five or six species, all differing in colour and the number and 

 proportion of the tentacula, are found in stagnant waters in 

 France. One of them, 



H. t'mrfis, Trembl., Pol., I, 1; Roes., Ill, Ixxxviii; Encyc, 

 LXVI, is of a beautiful light-green. It is particularly common 

 under the leaves of the Lemnse, and has been rendered cele- 

 brated as the first species on which the experiments relative to 

 the reproductive power of the genus Avere essayed. Tlie 



H. fusca, Trembl., Pol., I, 3, 4; Roes., Ill, Ixxxiv; Encyc, 

 LXIX, is more rare, and of a grey colour. Its body is not above 

 an inch long, and its arms are more than ten*. 



CoRiNE, Gcert. 



The Corines have a fixed stem terminated by an oval body, of a 

 firmer consistence than that of the Hydree, open at the summit and 

 completely covered with little tentacula. Some of them carry their 

 ova at the inferior part of. the bodyf. 



Cristatella, Cuv., 



Where there is a double range of numerous tentacula on the mouth, 

 curved into a half moon, forming a plume of that figure, which at- 

 tracts the nutritious molecules by their regular motion. These 

 mouths are placed on short necks attached to a common gelatinous 

 body which progresses in the manner of a Hydra. These animals 

 are found in stagnant waters in France. To the naked eye they 

 seem to be small spots of moidd ]:. 



VoUTICELLA, 



Where the stem is fixed, frequently ramous and much divided, each 

 branch terminating by a body shaped like a bell or horn. From the 

 aperture pi-oject two opposing groups of filaments which are con- 

 stantly in motion, and that attract nutritious molecules. The species 



* Add Hyd. grisea, Trembl., 1, 2; Roes., Ill, Ixxviii— Ixxxiii ; Encyc, LXVI I ; 

 —Hud. pollens, Roes. ; III, Ixxvi, Ixxvii ; Encyc, LXVIII ■,—Hyd. gelatinosa, Zool. 

 Dan., CXV, 1, 2. 



N.B. The ten first Hydrte of Gmelin are Actini?e, and the eleventh — H. doUolum — 

 a Holothuria. 



t Tuhvlaria coryna, Gm. ; or Coryne pitsilla, Gtert., App. Pall. Spicil., X, iv, 8 ; 

 Encyc, LXIX, 15, \6 i—Tubularia affinis, Gm.; Pall., lb., 9; Encyc, lb., 14;— 

 Hydra' muUicornis, Forsk., XXVI, B. b; Encyc, lb., 12, 13 ■,—Hyd. squamata, 

 Miill., Zool. Dan., IV; Encyc, lb., 10, 11 ;— and the species sketched by Base, 

 Hist, des Vers, II, pi. xxii, f. 3, 6, 7, 8. 



N.B. The gcniis Corine, which I have not observed myself, appears to merit re- 

 examination. 



1 Cm(atellamuctdo,C\xv.\ Roes., Ill, xcl. 



