116 ZOOPHYTES. 



less the tliin slice below. Tlie arms clasping at the summit belonged to 

 the animal most mature. Many more in the lower part of this series soon 

 became active ; but in the portion still under them were absolute quies- 

 cence and indefinite forms. Seven advancing Medusa in all might be 

 enumerated in the mass, in the course of this day, the 18th of February. 



The subject is accurately illustrated by a satisfactory representation, 

 Plate XVIII. fig. 13 ; enlarged, fig. 14 : Medusa most mature, a ; others 

 less mature, h ; slice of the fleshy basis, c. 



The importance of this fragment, the slice, apparently so insignificant, 

 will be shown afterwards. 



Next day, the 19th, at noon, a Medusa was observed to have quitted 

 the subject, necessarily the highest in the series, and hence at the upper 

 or larger part, and another swam at large in the evening. Further, a third 

 having escaped on the following evening, all these three were free. 



Next day, that is, on February 21, after vehement clasping at the 

 summit of the mass, a fourth was liberated, while new struggles to escape 

 appeared in the place it had left ; and on the morning of the 22d, six in 

 all were swimming in the water from further liberation during the night. 

 A seventh, freed on the 23d, swam with the rest ; and these seven, pursuing 

 their course, or suspended in equilibrio, resembled as many minute 

 stars. 



To ascertain more correctly what might follow, I thought it expedient 

 now to remove the whole, as they should have exhausted the number 

 whereof the severed conic frustum had apparently consisted on the 18th. 

 Still, the clasping of the arms of an eighth Medusa ensued, though not 

 liberated until next day, the 24th, at which time the inverted cone, or 

 series of animals, was much reduced from its earlier dimensions. 



At this juncture there was reason to conjecture that the smooth slice, 

 or basis of the subject, figs. 13, 14, c, adhering slightly to the watch-glass, 

 was something different from the animals successively quitting their posi- 

 tion above it, and that it was truly either an entire hydra, or a portion of 

 one. Besides, a spur such as described in the preceding chapter had 

 issued from it two days previously. 



A ninth Medusa, which had been clasping feebly for two days, also 



