Mr Daly ell on the Propagation of Scottish Zoophytts, 91 



strike upwards, those of the other strike downwards. Farther 

 diffusion of the basis adhering below forms additional compart- 

 ments for other hydra. 



The propagation of the Flustra carhasea^ foUacea, and trun- 

 cata, ensues after a similar fashion. A ciliated corpusculum, 

 spherical, ovoidal or irregular, quits the leaf, pursues its courses 

 in the water, becomes stationary, adheres, and a nascent flustra 

 arises from the spot. Above ten thousand such corpuscula have 

 been produced by a moderate sized specimen of the flustra,^ 

 liacea, tinging the bottom of a vessel yellow from their multi- 

 tude, and vitiating the water by their decay. 



III. Many of the Sertularia? propagate through the medium 

 of a minute, flattened, smooth being, with a regular gliding 

 motion, originating in the vesicles, which I have provisionally 

 denominated plamda, from its resemblance to the genus Pla- 

 naria. 



But a remarkable peculiarity occurs in the Sertularia dkhoto^ 

 ma, or Sea thread, one of the most elegant and delicate of the 

 tribe; where 1500 or 2000 living hydrae sometimes adorn a 

 single specimen. Its vesicles are rarely found ; when present they 

 are in the proportion of about one to thirty hydrae, difi*ering in 

 nothing externally from the general aspect of others ; replenished 

 also by twenty or thirty greyish corpuscula, with a dark central 

 nucleus. At first, all are immature and quiescent, but motion at 

 length commences : the corpuscula become more distinct ; seve- 

 ral slender arms protrude from the orifice of the vesicle, which 

 are seen in vehement action, and, after many struggles, an ani- 

 mated being escapes. But this has no relation either to the 

 planula of the Sertularia?, or the corpusculum of the flustra, 

 alcyoniuni, or actinia. It might be rather associated with the 

 Medusariae. Before ascertaining its origin, I had named it Animal^ 

 culum tintinnabulum, from its general resemblance to a common 

 hand-bell, for the purpose of recognition. 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 

 pendent from the lip below. These are of muricate structure, or 

 rough, and connected to the lip by a bulb twice their own dia- 

 meter. The summit of the crest unfolds occasionally into four 



