392 POLYPI. 
substance but a diaphanous parenchyma filled with more opaque 
granules. Notwithstanding this, they swim, crawl, and even walk 
by alternately fixing their two extremities in the manner of Leeches ¢ 
or of the caterpillars called Geometre. They agitate their tentacula 
and use them for seizing their prey, which can be seen being digested 
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, 
Hi. viridis, Tremb., Pol., I, 1; Roes., III, lxxxviiis; Encyc., 
LXVI, is of a beautiful light-green. It is particularly common 
under the leaves of the Lemnz, and has been rendered cele- 
brated as the first species on which the experiments relative to 
the reproductive power of the genus were essayed. The 
Hi. fusca, Tremb., Pol., I, 3, 43 Rees., III, 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(1). 
CorInE, Gert. 
7 
The Corines have a fixed stem terminated by an oval body, of a 
firmer consistence than that of the Hydra, open at the summit, and 
completely covered with little tentacula. Some of them carry their 
ova at the inferior part of the body(2). 
(1) Add Hyd. grisea, Trembl., 1, 2; Res., IM, Ixxviii—Ixxxiii; Encye., LX VII; 
—AHyd. pallens, Res. ; Wi, lxxvi, lxxvii; Encyc., LX VU1;—Hyd. gelatinosa, Zool. 
Dan., CXV, 1, 2. 
N.B. The ten first Hydre of Gmelin are Actiniz, and the eleventh—Z. dolio- 
lum—a Holothuria. 
(2) Zubularia coryna, Gm.; or Coryne pusilla, Gert., App. Pall. Spicil., X, iv, 
8; Encyc., LXIX, 15, 16;—Tubularia affinis, Gm.; Pall., Ib., 9; Encyc., Ib., 14;— 
Hydra multicornis, Forsk., XXV1, B. b; Encyc., Ib., 12, 13;—Hyd. squamata, 
Mull., Zool. Dan., IV; Encyc., Ib., 10, 11;—and the species sketched by Bosc., 
Hist. des Vers, H, pl. xxi, f.135%0,.7, 8. 
N.B. The genus Corine, which I have not observed myself, appears to merit 
re-examination. 
