1]4 Mr. H. J. Carter on the Development of Gonidia 



cells filled with minute refractive granules frequently make their 

 appearance within the mucus-layer of the cell, and when the 

 former shrinks from the sides of the latter, these spherical cells 

 become wrapped up in it (fig. 9 a). In this position, if their 

 granular contents, which the sequel will show to be germs, were 

 to be liberated into the cell of Spirogyra through the bursting 

 of their parent-cells, they would in all probability perish, for the 

 parent-cells have apparently already subsisted, and brought their 

 progeny to the state of germs, on the nutrient contents of the 

 cell of Spirogyra in which they have become developed. But to 

 provide for this, these spherical cells have each the power, not 

 only of developing a blind tube, which by the process of solution 

 to which I have adverted can pass through the cell-wall of the 

 Spirogyra for the exterior liberation of their germs, but also to 

 tubulate with each other if necessary, when the contents of all 

 the cells together may be thus liberated by one or more tubes 

 only, as the case may require (fig. 9 b) ; and often they will send 

 one through the septum of the cell into the resting-spore of the 

 next cell, which being full of nutritious matter, immediately 

 furnishes food for the whole brood (fig. 10 e). Hence if a bhnd 

 tube of a small cell of this kind can make its way through these 

 comparatively hard membranes by simple solution, for it can 

 hardly be supposed that it does so by any mechanical power, 

 the smallest germ may be able to enter the cell or sheath of a 

 filamentous Alga after the same manner. That the granules of 

 these spherical cells, which are of difi*erent sizes, and, motionless 

 at first, become locomotive, swarm about the cell, and then pass 

 out of the tubular prolongations, has been proved to me by ocular 

 demonstration (fig. 9 b'). 



Thus I think sufficient evidence has been brought forward to 

 show, that the globular vesicle of the mucus-layer or proto- 

 plasm in the cells of the Characese is a parasite, probably of a 

 rhizopodous nature, apparently introduced after the development 

 of the young plant, and not impossibly under the form of a 

 germ, and after the manner of the instances last mentioned. 



I have yet however to add a few observations on developments 

 of a similar kind in the cells, not only of Spirogyra, but in the 

 body of an infusorium, viz. in Euglena. 



During conjugation, the Spirogyrce are particularly infested 

 with these parasites, if such they may be termed, and the rapidity 

 with which they make their appearance at this period would lead 

 to the conclusion that the germs from which they originate 

 must have pre-existed in the cells in which they appear, as in the 

 Characese ; that is to say, without interfering with their func- 

 tions. Be this as it may, the peculiar tubulating cell just men- 

 tioned is very commonly seen in Spirogyra at this time (figs. 



