and other Indigenous Rhizopods. 441 



porized part of the organism, and that, in many cases, the layer 

 of protoplasm which constitutes it during the extrusion of effete 

 matter, and occasionally also of minute but perfectly formed 

 Amoeba, is actually disengaged along with the object whose 

 egress from the main body it presides over and probably effects ; 

 so that even here we encounter phenomena which, although as 

 yet inexplicable, tend directly to prove the accuracy of the 

 views referred to. In short, the vacuolar sac becomes the 

 tubule, being in some cases reabsorbed into the substance of 

 the body, in others actually expelled entire, as shown in PL IX. 

 figs. 3 & 4. 



Again, it appears to me that, assuming the hypothesis to be 

 admissible, we not only render intelligible the mysterious and 

 otherwise inexplicable properties of sarcode, but find a clue to 

 the determination of the function performed by the contractile 

 vesicle. 



I am able fully to confirm the statement of Carter that this 

 body invariably discharges itself externally in the Rhizopods, 

 although aware that this view is opposed by M. Lachmann and 

 others. The orifice through which the discharge of its watery 

 contents is effected is not of a permanent nature, but, like the 

 tubule occasionally seen in the region of the villi, comes into 

 existence only under the operation of the force that distends the 

 wall and eventually bursts it. We frequently see that the systole 

 of the vesicle is interrupted before the entire obliteration takes 

 place, which most commonly occurs. But it is a mistake to 

 suppose that the circular outline then left, and which forms the 

 basis, as it were, of the vesicle when renewed, represents the 

 orifice by which the contained fluid escaped. That orifice we 

 can very rarely detect, even under the highest powers of the 

 microscope*. I can personally speak to its subtle but neverthe- 

 less appreciable character, having watched its action for a con- 

 siderable period on two occasions, in Bengal — namely, in an 

 Amoeba closely allied to, if not identical with, A. villosa, and in 

 a Kerona, its distinctness in the Infusorial animalcule being 

 only rendered greater by the greater ease with which the latter 

 was maintained in the position best fitted to carry on the ob- 

 servation. 



Mr. Carter, in describing the contractile vesicle (he. cit.), says 

 it is neither a circulatory nor a respiratory, but an excretory 

 organ, and, referring more particularly to Amoeba and Actino- 

 phrys Sol, he adds, — " During the act of dilatation, the vesicula 

 projects far above the level of the pellicula, even so much so as 



* I would distinctly guard myself against appearing to convey the idea 

 of a valvular opening such as is supposed to exist by Weston in Actino- 

 phrys Sol (Quart. Journ. Micr. Soc. vol. iv. p. 116). 



Ann. % Mag. N. Hist. Ser. 3. Vol.xi. 29 



