HYALINE PSEUDOPODIA 105 



They recall similar appearances which have been described 

 above in the reticular pseudopodia. But the clearest proof 

 of the sudden conversion of hyaline into reticulated proto- 

 plasm is furnished by what takes place during the retraction 

 of the pseudopodium. This process is always commenced 

 by the pseudopodium suddenly becoming limp and flabby, 

 and thrown into wavy curves. It may next, without further 

 noticeable alteration, gradually diminish in size, and finally 

 disappear entirely, or, not infrequently, it becomes bent 

 back towards the fibrous tuft, or towards other pseudopodia, 

 and then fuses with them. In other cases, on the contrary, 

 the following interesting process can be observed. The 

 pseudopodium, which has become wavy in outline, first 

 acquires a granular appearance, as darker points make 

 their appearance in its course. It then contracts into an 

 irregular form, and, pari passu, with this process it becomes 

 continually more distinctly reticular in structure, until it is 

 seated finally on the hyaline larger pseudopodium, like 

 one of the irregular reticulate protoplasmic masses already 

 mentioned, from which it took its origin. On Plate I. Fig. 

 3, a, is depicted a pseudopodium of this kind in process of 

 retraction, which has already become distinctly reticulate in 

 two places, and Figs. 3, b and c, represent two stages of the 

 retraction of the pseudopodial branch *, which became dis- 

 tinctly reticulated in the process, and fused with the reticu- 

 late process of the other side **, also probably a retracted 

 lateral branch, to form the reticulated terminal appendage 

 of Fig. 3, c. 



If the fibrous tuft of the shell opening be pressed slightly 

 with the cover -slip, its fibro- reticular protoplasm easily 

 changes into protoplasm of a quite homogeneous appearance, 

 which protrudes from the tuft in the form of lobose 

 hyaline processes, but it undergoes a reticular modification 

 after a short time, whereupon the tuft obtains its normal ap- 

 pearance again. Within the shell also, whenever the proto- 

 plasm in the region of the aperture was slightly retracted 

 from the envelope, I frequently observed irregular, com- 

 pletely hyaline, amoeboid protoplasmic projections of this 

 kind. With these it was similarly possible to follow the 



