Mr. H. J. Carter on Ploesconia and Kerona. 253 



The Oscillatoria had been obtained from the salt-water drain 

 of Bombay, where it floats in dark-green silky clots, and the 

 clots placed in a basin of fresh water on the 16th May, 1855. 

 Six days afterwards, during which a host of Vorticella microstoma 

 had made their appearance, and had for the most part become 

 encapsuled, Kerona pustulata (figs. 5-7) appeared. 



On the seventh and eighth days the Keronce had increased to 

 an inconceivable number, apparently from fissiparation, and 

 on the ninth day they began to become encapsuled, when a 

 quantity of them, in all stages of this process, complete and in- 

 complete, were transferred to a watch-glass filled with fresh 

 water. 



During encapsulation, the first change that presented itself 

 was the absence of all crude aliment in the abdominal cavity; 

 then a division of the nucleus into four parts, preparatory to its 

 disappearing altogether ; at the same time, certain dark angular 

 grains, which had been floating round with the sarcode of the 

 abdominal cavity, became congregated into the posterior extre- 

 mity (fig. 6 e) . The Kerona now became shortened ; its cilia 

 gradually disappeared (fig. 8) ; and finally it passed into a 

 rounded oval ball (PL VI. fig. 9). This, after a certain time, 

 resolved itself into an obtuse elliptical capsule enclosing a sphe- 

 rical cell with a separate mass of dark angular grains (fig. 10) ; 

 the capsule {a) was laminated and ragged on the outside, and 

 defined by a clear line internally, while the spherical cell {b) 

 contained all the vital remains of the Kerona, together with the 

 contracting vesicle, but exclusive of the " dark angular grains" (e), 

 which, adhering more or less together, were still enclosed within 

 the capsule, and thus formed an excellent distinguishing mark 

 for it throughout the experiment. At this time the spherical 

 cell was rotating, probably from the presence of cilia on its sur- 

 face, and the contracting vesicle active (c) ; but subsequently 

 the granular mucus of which it was composed became trans- 

 formed into a number of uniform, round, refractive, oil-looking 

 bodies [d), and the contracting vesicle disappeared. 



In this state, up to the 14th of June, that is, thirty-six days 

 after they had been placed in the watch-glass, which was kept 

 constantly filled with water, they remained unchanged, and no 

 other organisms were present but a few Amoeba and Vorticella 

 microstoma ; when, having waited much longer than the time 

 mentioned by M. J. Haime for the metamorphosis, I thought 

 that this still-existence might be owing to the absence of nutri- 

 tive matter. Accordingly, having some portions of dried Nostoc 

 at hand, a few of these were placed in water, and when they had 

 become gelatinous, their soft parts were squeezed through a 

 piece of fine cambric into another watch-glass, to which a por- 



