216 Dr Barry on Fissiparous Generation. 



consisting, as I shewed, in the division of a pellucid mass 

 (hyaline) situated in the centre of each cell. And it is de- 

 serving of remark, that Ehrenberg describes his Monas bicolor 

 (fig. 7.), evidently a nucleated cell, as possibly an early state 

 of the Chlamidomonas just mentioned (fig. 4.)* 



57. The curiously symmetrical forms of many of the Bacil- 

 laria appear to be due to the same division and subdivision 

 of the pellucid nuclei or hyaline of cells. 



58. The delineations of Gonium, Monas vivipara (fig. 5), 

 and Ophrt/dium, given by the great naturalist just mentioned, 

 afford satisfactory examples of a pellucid body dividing and 

 subdividing like the nucleus of a cell. 



59. In many other of Ehrenberg' s figures of the poly gastric 

 Infusoria, the corresponding part appears to me to be denoted 

 by a blue, red, or green colour, according as there had been 

 added either indigo, carmine, or sap-green. This accords 

 with what has been mentioned in a former page regarding 

 cells — that a foreign substance becomes added and assimilat- 

 ed through the nucleus. Fecundation of the ovum takes 

 place in the same manner as nutrition of the cell, and seems 

 comparable to the nutrition of one of the Infusoria.t 



60. But farther, I recognise in Ehrenberg's delineations of 

 the Infusoria, not merely a cell-formation, but everywhere the 

 existence of transitory or assimilative cells. 



61. And farther still : the infusorial cells, like the cells of 

 larger organisms, have their origin in globules which become 

 discs or "cytoblasts;" these passing through stages correspond- 



* " I had often remarked," says W. Addison (loc. cit. p. 43), " the very great si- 

 militude of size and appearance between several forms of the polygastric animal- 

 cules, and some of the varieties of pus corpuscles. So great is this similarity, that, in 

 many instances, it would have been difficult to distinguish the one from the other, 

 had it not been for the voluntary and very active movements of the animalcules." 

 The same author adds, that when a polygastric animalcule is touched by liquor 

 potassae, its body bursts, and liberates the particles called stomachs ; from which, 

 and from other circumstances mentioned by Addison, Dr Carpenter infers that 

 the particles in question '' are cells which float in the fluid of the body, and ela- 

 borate the materials for its nutrition, in the same manner as do those of the chyle 

 and blood of higher animals." — (Carpenter, loc. cit., p. 274.) 



t The orifice in the wall of the germinal vesicle and in that of other cells ap- 

 pear also, in some instances, at least, to correspond to the " mouth" of the Infu- 

 soria ; this " mouth" having apparently once been an orifice in the parietal nu- 

 cleus of a cell. 



