of the 'Trichodina pediculus (?). 273 
sketch of the animalcule at this stage of development, it happened 
unfortunately, that, im the instant, the first vesicle had detached 
itself and floated away, leaving the second free at the margin. 
Moreover, it is to be noted, that, after the disappearance of 
this first sac, two spherical granular bodies similar to those I had 
thought to be present in it were still perceptible, occupying the 
same relative position to one another (fig. 12). 
Watching the progress of the second sac up to eight o’clock, 
I saw it gradually make its way outwards, leaving more and more 
of the parent-bemg free. The latter still presented numerous 
small globules and greenish particles. Having subsequently 
made compression, the process of detachment was hastened, and 
at length completed, the second sac becoming independent. How- 
ever, this interference with the natural progress of development 
seemed to arrest its activity, for the detached bud showed no in- 
dication to move away, and the parent animal was left broken 
and misshapen, but still retaining its green globules and particles 
(fig. 12). 
Remarks.—The process of development above described may be 
called one of internal gemmation, and is distinct from that of 
spontaneous fission, as detailed by authors, although in some of 
its phenomena and phases it may resemble it. M. Dujardin 
would restrict the modes of propagation of the true Infusoria, or 
so-called Polygastrica, to that by spontancous fission, and, occa- 
sionally, by gemmation. But im the animalcule observed by me, 
we certainly ‘find another mode in operation, more akin to gene- 
ration by ova, which Ehrenberg considers to occur, although that 
most able microscopist would seem to have founded his opinion 
on other observed appearances, interpreted by Dujardin as due 
to the process of ‘ diffluence.’ 
It would have been very gratifying to me to have been enabled 
to follow the detached bud, and to have watched the changes it 
might have undergone. I have since met with diaphanous vesicles 
similar in character, devoid of any distinct nucleus, contaming 
only some small particles of greenish matter, but have never been 
able to discover a very decisive progress in thei development. 
However, this fact is certain, that the product of the animalcule 
observed did not partake of its distinctive characters, but was 
merely a simple non-ciliated cell. Such characters truly might be 
subsequently developed in it, or in another being derived from 
it, in accordance with the phenomenon of ‘alternation of genera-- 
tion’ of Steenstrup, or with the truth-bearmg hypothesis of Prof. 
Owen, of an active ‘ spermatic force.’ 
It beg much more my purpose in writing this paper to re- 
cord an observation than to speculate upon it,—leaving the latter 
to others more capable than myself,—I shall conclude by merely 
