74 



ANDREWS. 



and which becomes rhythmically more fluid, I have even seen 

 yolk transferred from one "cell " to the other. In fine, there 

 are strong optical reasons for refusing to hold that the cell wall 

 is a true isolator of portions of the substance in a mass, and for 

 inclining to believe that the living substance may overstep them 

 at times in its more intimate functions which as yet we cannot 

 hope to trace fully. 



Perhaps the most striking and significant cases of filose 

 activity found were in the developing eggs of starfish and sea- 

 urchins. Protoplasmic activities of the pellicular substance were 

 seen throughout the normal development of starfish and sea- 

 urchin eggs, notably the former. The phenomena were observed 

 in two different species of each group, had from two widely 

 separated localities in two succeeding years. Many camera 

 drawings were obtained both of normal and abnormal eggs.^ 



The filose processes were in the main invisible except with 

 the 2.0 mm. immersion with the 8-18 oculars. 



The spinnings contained granules in their usual form, and 

 also in their reduction form, when they were no longer visible 

 except as a changed optical quality of the substance which 

 then appeared quite structureless. The vesiculation of the proc- 

 esses was much finer, as a rule, than that of Butschli's struc- 

 ture, and in the normal ^^g the extensions were wholly of the 

 finer, pellicular, foam. In most other respects they were typi- 

 cally protoplastic, of a radiolarian type. The filose activities 

 seemed to be continuations in kind of those which produce the 

 tuft to receive the sperm in the sea urchin ; and in starfish 

 accompany extrusion of the polar globules. They arose from 

 the general periphery of eggs before cleavage and thereafter 

 from the whole periphery of each cell as fast as it formed, 

 ceasing only where and when cell surfaces were again fused 

 with one another. 



The activities were maintained in normal eggs by pellicular 

 material alone, or by this reinforced from underlying, interalve- 

 olar, material. That it could be as last stated was manifest in 



^ As I have recently published in the Journal of Morphology a detailed 

 account of these phenomena, I will refer the reader to that article for fuller 

 accounts of many facts more briefly passed in review here. 



