JOURNAL 



OF THE 



ROYAL MICROSCOPICAL SOCIETY. 



APEIL 1884. 



TEANSACTIONS OF THE SOCIETY. 



III. — Observations on the Life-History of Stephanoceros 

 Eichhornii. By T. B. Eossetbr, F.E.M.S. 



{Read Sth November 1882, and 12th March 1884.) 

 Plate V. Figs. 1-3. 



In the course of some observations to verify the fact that the 

 cell of Stephanoceros Eichhornii is tubular, I determined to try the 

 experiment of freeing the creature from its cell. I accordingly 

 took a fine and healthy individual from my tank, placed it on the 

 plate of the live-box with a small quantity of water, and after care- 

 fully observing it with a 1/2 in. objective and C eye-piece, I 

 made an incision in the cell, and severed the creature's tail just 

 above the sucker. After paring down the leaf to which it was 

 attached, and substituting a 2-in. objective, I took a very fine 

 lancet, and steadying the leaf with a needle and watching my 

 opportunity, I severed the muscles, cutting the tail through close 

 to the base, and I had the gratification of seeing it swim out of the 

 cell, leaving the cell perfectly intact. I subsequently again tried 

 the experiment, with the following results (extracted from my 

 diary). 



On Monday, May 15th (10 p.m.) I placed a good specimen of 

 Stephanoceros Eichhornii in a moderately deep circular trough with 

 a square base, my object for so doing in preference to using the 

 live-box being to ascertain what amount of vitality existed after 

 disconnection. This time, instead of merely making a small 

 incision in the cell, I cut it straight across, completely dividing 

 the cell, a small portion with the lower end of the tail being left 

 attached to the piece of weed. The other, containing the animal 

 and the greater portion of the cell, I dragged away into the 

 middle of the trough, and awaited results. At first the creature 

 did not attempt to move, its tentacles being completely closed up 



Ser. 2.— Vol. IV. N 



