600 FOURTH REPORT — 1834. 



blish itself independently. It never drops from the parent, but 

 often, when yet immature, buds are germinating from its 

 sides, while the opposite side of the parent enlarges also ; the 

 whole presenting a shapeless and distorted congeries, which is 

 refined by time into separate, distinct, and perfect animals. 

 A single specimen had eighty- three descendants in thirteen 

 months, nor were its prolific powers then exhausted. 



Some authors have maintained that the Hydrce of fresh 

 water propagate by buds at one season, and by ova at another. 

 Nothing of this alternation occurred in the course of the au- 

 thor's observations, protracted during five years, on an original 

 group, and the posterity of these marine Polypi. 



The locomotive faculties of the Actinice and the Hydrce are 

 exercised very seldom, and on the most limited scale. 



3. Tuhularia indivisa. — A splendid stem rooted below, and 

 rising thirteen inches high, is crowned by a scarlet head, bear- 

 ing some correspondence with the structure of the former 

 animals. The mouth is situated in the centre, amidst forty or 

 fifty less active filaments, and the margin is surrounded by 

 thirty or thirty-five tentacula, expanding fourteen or fifteen 

 lines between their opposite tips. A tenacious yellowish matter 

 fills the tubular stem, which is frequently discharged in con- 

 siderable quantities if the root be ruptured. 



Splendid groups are formed by fifty or even a hundred spe- 

 cimens of this zoophyte, in immediate approximation. 



An ample ovarium, resembling clusters of grapes, is borne 

 externally on the head, and weig-hing it down by its exuberance. 

 On approaching maturity the ovum drops from its cluster for 

 evolution below, where slight prominences soon denote incipient 

 tentacula, as in the Hydr<s, while incorporated with the parent. 

 But, as they extend, a knot enlarges their extremities, contrary 

 to their ultimate acute formation in adults. Next, the nascent 

 animal, reversing itself, enjoys the faculty of progression by 

 means of the inverted tentacula, as on so many feet, apparently 

 to select a site ; when, again resuming the natural direction with 

 the extremities upwards, the lower surface fixes itself below, 

 and roots there for ever : meantime elongation of the stalk 

 raises the head amidst its watery element. 



It is evident, therefore, that the Tuhularia indivisa, though 

 subsequently rooted as a plant, is originally of animal nature 

 exclusively. 



The head is deciduous, generally falling from the stem a 

 short time after removal from the sea ; but regeneration ensues 

 at intervals of from several days to se\ eral weeks, though the 

 successive heads are never equally luxuriant, nor bear a prolific 



