CAMPANULARIA. 215 



rest from the branches. All were entirely new. The reproduction had 

 rose 30 lines, yet its energies were not exhausted, as shewn by farther ad- 

 vances. 



Here, after ten spines had been generated, an eleventh shot from the 

 stem on September 20, — next day the hydra was about to flourish. A 

 needle had then forked off it, and hydrse from both were displayed on the 

 22d. The hydra from the needle decayed in 24 hours. That from the 

 spine subsisted three or four days. The twelfth hydra, mature also on 

 the 22d, decayed in three or four days ; so that the animals originating 

 from the reproduction had little permanence. 



Propagation. — From anything yet said on this subject, it seems ques- 

 tionable whether the precise mode whereby the Sertularia dichotoma per- 

 petuates its race is sufficiently explicit. Perhaps it may be found to bear 

 more than one kind of vesicle. 



On rare occasions I have seen numerous ovate vesicles borne by 

 this Sertularia among the bells containing living hydrae, and in the propor- 

 tion of about one to thirty of the latter. Their position is no farther 

 l)eculiar, than in being seated on the upper side of the branches ; and they 

 are generally empty, as if having fulfilled their purpose. When present, 

 their numbers on a branch sometimes amount to eight or ten. 



These vesicles are of a grey or a greenish colour. When prolific, they 

 contain twelve or more dull grey corpuscula, each with a dark central 

 nucleus, and all as if compressed together. — PI. XLI. figs. 4, 6. They are 

 void of any resemblance to the corpusculum in the vesicles described of 

 the other Sertularias, developing from a globular form, and escaping as an 

 active planula from the orifice of the vesicle. 



When the contents of that now in question approach maturity, some 

 internal motion is betrayed towards the summit of the vesicle ; the tijjs 

 of the tentacula of an included animal protrude ; then stretching farther, 

 they clasp convulsively, as if to free the body within. After much appa- 

 rent exertion this is gradually accomplished, but instead of the accustomed 

 planula, we next behold a creature allied to the Medusa, which has 

 escaped from its prison. 



At first I could scarcely credit the truth of so unusual an occurrence ; 



