314 Phillips on a Comparative Study of the 



ence of relation between the two movements." Zukal (98) 

 also regarded the motion of Spirulina as intimately asso- 

 ciated with growth of the organism, and as comparable to 

 the growth of a tendril. 



Palmer (61) has observed in Eunotia major, proto- 

 plasmic processes at the corners of the frustules, which he 

 called "coleopodia," which were connected with a thin layer 

 of protoplasm or "coleoderm" surrounding the whole dia- 

 tom. He said : "The above results of observations and ex- 

 periments would seem to be conclusive proof that E. major 

 and by inference other nearly related species and genera of 

 the Fragillariese move by the action of organs that may be 

 called coleopodia. This conclusion, however, is far from 

 touching the question of the means of locomotion in Pinnu- 

 laria and its allies. It may be added, in this connection, 

 that while a large Pinnularia in rapid motion not infre- 

 quently gives evidence of brisk internal currents, such as 

 Miiller (56) has described, such currents have not been 

 observed by me in Eunotia. Under rather high powers one 

 only sees, near the corners of the frustules, in the vicinity 

 of the raphe, a certain internal commotion among the very 

 small protoplasmic granules, a spasmodic movement back 

 and forth, a waving about. This movement differs alike 

 from the streaming of cyclosis and the Brownian trembling, 

 and it is traceable with difficulty, if at all, far from the cor- 

 ners. Nevertheless, the channelling of the frustules is of a 

 character to indicate the existence of currents, and further 

 observations may yet reveal them." 



Barkas (2), in speaking of the movement of Bacillaria 

 cursoria, observed that "the small, gritty particles on the 

 sides of the frustules moved freely backwards and forwards, 

 in a hurried manner along the edge of the frustules, as 

 though they were occasionally driven by cilia, or as if they 

 had automatic or voluntary motion. I observed that they 

 moved when the diatom remained stationary." 



It seems to me that the osmotic theory can hardly account 



