ME:DUSA bifida. 115 



was surprised that, amidst such an host of enemies to all living creatures, 

 — those mercilessly devouring whatever they could master — the Medusa 

 should dwell with impunity, involved by the very organs of capture. 



On dislodging the subject, apparently a hydra of medium size, with 

 scissors, and transferring it to a watch-glass, nothing but the wonted con- 

 vulsion, which proceeded from the clasping of the arms of a Medusa 

 upon the surface, disc, or extremity, was seen on the morning of the 17th. 

 However, several were swimming at large next day ; the size of the sub- 

 ject had diminished, and it was visibly indented by deep corrugations. 



But now I found, and in good time for correction, that I had been 

 somewhat mistaken, as instead of a Medusa having been detached entire 

 by the sharp pointed scissors employed, I had severed only the corrugated 

 portion, along with a slice of the smooth fleshy basis sustaining it, as will 

 be better understood in the sequel. In fact, the position of the subject 

 precluded the free use of the instrument designed for insinuation of the 

 points below each side of the apex, so that the edges had been applied. 



The vessel whence this subject was removed contained a colony ori- 

 ginally consisting of ten hydrae, which invested the empty shell of a Ser- 

 pula, as described in a preceding paragraph. There the colony dwelt, fed, 

 and bred by uninterrupted gemmation. Thus it was occasionally aug- 

 mented naturally, and reduced accidentally, until in three years and three 

 months not fewer than the number above mentioned, at least 100 of its 

 members remained. 



No other animal had been introduced among them. 



The hydra, as observed, in its proper site is suspended by the apex, 

 at some elevation, whence the body hangs down so as to afford free scope 

 for the exercise of the descending tentacula. Therefore colonies in con- 

 finement disperse on the sides of the glass as most congenial to their nature. 

 But the diminished proportions of the apex, which would be otherwise a 

 sustaining base, sometimes renders their position so insecure that they drop 

 from it. 



Returning to the subject in the watch-glass, it resembled an inverted 

 conic ftustum of yellowish colour about three lines in length, proving then 

 and ultimately to be wholly composed of Medusae, in various stages, un- 



