Laomedea. 
Z. HYDRGIDA. 
15J 
in general, clothed with cilia and moveable. Every three of them 
are inclosed, while in the vesicle, within a thin transparent motion- 
less capsule, presenting at its free extremity several stiff, straight 
diverging pointed processes, which Ellis mistook for the tentacula of 
a young polypus. Dr Grant. 
Sir John G. Dalyell has made some singular observations on this 
species, which seem irreconcileable with those of Professor Grant and 
Cavolini. He tells us that it rarely produces vesicles. When pre- 
sent they contain from 20 to 30 greyish corpuscula with a dark cen- 
tral nucleus. 44 At first, all are immature and quiescent, but motion 
at length commences : the corpuscula become more distinct ; several 
slender arms protrude from the orifice of the vesicle, which are seen 
in vehement action, and, after many struggles, an animated being es- 
capes. But this has no relation either to the planula of the Sertu- 
lariae, or the corpusculum of the Flustra, Alcyonium, or Actinia. It 
might be rather associated with the Medusarise. Before ascertaining 
its origin, I had named it Animalculum tintinnabulum , from its gene- 
ral resemblance to a common hand-bell, for the purpose of recogni- 
tion. This creature is whitish, tending to transparency, about half 
a line in diameter ; the body is like a deep watch glass, surmounted 
by a crest rising from the centre, and fringed by about twenty -three 
tentacula pendant from the lip below. These are of muricate struc- 
ture, or rough, and connected to the lip by a bulb twice their own 
diameter. The summit of the crest unfolds occasionally into four 
leaves, and four organs prominent on the convexity of the body, ap- 
pear at its base. When free, the animal swims by jerks, or leaps 
through the water, or drops gently downwards ; it is invited to move 
by the light, and it has survived at least eight days. Then it disap- 
pears, at least I have not been able to pursue its history longer. No 
other product has ever issued from the vesicles of the Sertularia di- 
chotoma.” Edin. New Phil. Journ. xxi 91-2. 
2. L. geniculata, stem zig-zag , simple or sparingly branch- 
ed ; cells on annular stalks from the joints , alternate , campanu - 
late , the rim plain ; vesicles ovate. Doody. 
Plate XXI. Fig. 1, 2. 
Corallina confervoides gelatinosa alba, geniculis crassiusculis pellucidis, 
Raii, Syn. i. 34, no. 7. -Fucoides setaceum tenuissime alatum, Ibid. 
38, no. 6, pi. 2, fig. 2. Ellis, in Phil. Trans, abridg. x. 491, pi. 12, fig. 
I, a> A. Knotted-thread Coralline, Ellis, Corail. 22, no. 19, pi. 12. 
b. B Sertularia geniculata, Lin. Syst. 1312. Pall . Elench. 117. 
Mull. Zool. Dan. tab. 1 1 7, fig. 1-4. Ellis and Soland. Zooph. 49. Berk. 
Syn. i. 218. Turt. Gmel. iv. 682. Wern. Mem. i. 564. Turt. Brit. 
Faun. 215. Stew. Elem, ii. 446. Bose, Vers, iii. 117. Lam. Anim. s. 
