Filaments in Surirella hifrons. By John Badcock. 353 



in which the Surirella were found, and was struck with the 

 similarity between the filmy projections in Arcella difflugia 

 with those of the diatom. Although those of the Arcella were 

 much larger, yet the fine non-granular character was the same, 

 as also their variableness and irregularity. They were simply as 

 fine pencil shadings or smoke-like semi-transparent films, which in 

 the Arcella were larger and of a more pronounced character than 

 in Surirella, yet of the same amoeboid nature in both. 



As I was thus led — accidentally as it were — to compare these 

 two forms of life, it seemed to me that the only essential diff'erence 

 between them was one of size. In this light one could hardly 

 regard the diatom as of the vegetable kingdom pure and simple. 

 However, my object is not to raise this vexed question of animal or 

 vegetable nature, but simply to put on record my observation of 

 these filmy protuberances as corroborative of previous observations 

 made and recorded by other and more eminent workers in this 

 department, but which of late years have been generally either 

 ignored or considered as of no special significance. 



I will only say that had I not seen a diatom before, or known 

 anything of its classification, I should certainly have regarded this 

 Surirella as a testaceous Amoeba. 



The special optical power and arrangement necessary to see this 

 phenomenon in the diatom may be a subject of interest. I have 

 only one objective with which I can see it distinctly (a 1/2 in.). 

 It was strange and inexplicable to me that neither a higher nor 

 lower power revealed it. 



Now, whether there is any physiological problem involved, 

 or any special relation between the structure of the eye and 

 this particular optical power, may be a question worth further 

 investigation by those competent to undertake it. I merely throw 

 it out as a suggestion, which may or may not be worth anything. 

 One thing is, however, desirable, and that is that such special aids 

 should be sought as would enable any one readily to verify such 

 observations for himself, for it seems certain that disputes arise and 

 contradictions are made which a little more attention to this point 

 would probably prevent. 



Ser. 2.— Vol. IV. 2 B 



