FLUSTRA. 25 



earlier brood would affix to the side of the vessel, immediately under the 

 surface of the water, and that, on farther replenishment, any second or 

 later brood, attaining maturity, would be found affixed in a higher position 

 than that which had preceded it. 



A series of experiments on the propagation of the present species 

 was attended with a similar result. The corpuscula preferred the lighter 

 side of the vessel, and the later brood became affixed above that which 

 was produced previously. 



No remarkable peculiarities distinguish these gemmules or corpus- 

 cula. A curving prolongation, apparently for securing the foundation, 

 extends one of the extremities after their adhesion, fig. 11 ; and from the 

 opposite part rises an originating leaf, wherein the hydra is generated, 

 figs. 12, 13, which may succeed in eight days from the liberation of the 



gemmule. 



Now it is discovered that the cell lias an oval orifice, and that it is 

 guarded by five spines. But they did not appear in all which had been 

 bred from gemmules : also their number is variable, and their presence 

 uncertain in the adult. The nascent hydra has about twelve tentacula. 



The young product appears forking from the same root, as with two 

 hydra?, probably from two approximated corpuscula adhering to the sur- 

 face of the vessel. — Fig. 12. 



A second nascent hydra originates on the same side of the leaf, higher 

 than the spot where the first has decayed. — Fig. 13. 



A number of filaments, affixing themselves, shot forth from the 

 extremity of two specimens that had been severed from the stem, which 

 must be rather considered analogous to the spinous vegetation so often 

 generated from zoophytes, than as natural roots designed for security. 



Many avicularia, such as above described, are seen on this product, 

 which may possibly affect its precise position among the Flustrse. Some 

 remained active during nearly three weeks. 



This species is usually founded on solid substances. The lower part 

 of fig. 2. had been rooted near a sponge, now advancing beyond it. 



Fine specimens, or indeed specimens of any quality, are uncommon. 

 VOL. II. D 



