THE APPARATUS OF LOCOMOTION IN SURIRELLA. 



BY T. CHALKLEY PALMER. 



In a recent article in these Proceedings the views of R. 

 Lauterborn on mechanism of motion in diatoms were dis- 

 cussed to some extent, and were not found quite satisfactory. 

 Notwithstanding the beautiful and sometimes profound studies 

 of this able investigator — studies that should lend a certain 

 weight to his opinions — his conception of propulsion by- 

 means of out-flowing coleoderm-substance {Gallerte) leaves 

 the patient student of the moving diatom quite dissatisfied. 

 The actual observer cannot reconcile this theory with numer- 

 ous characteristics of diatom motion. Neither is the matter 

 improved by the learned author's endeavor to correllate the 

 motion of these organisms with that of Closterium and Oscil- 

 laria. As to these and their motions, indeed, while it would 

 not be strictly correct to say that everything has been cleared 

 up, certainly a good deal of water has run under the bridge 

 since 1896. But that is distinctly another chapter, and there 

 is no need to do more than refer to it here. 



My present object is to record some notes on renewed 

 studies of the moving diatom, mostly made since the writing 

 of the article referred to ; studies that enable me to reenforce 

 the argument from the nature of the phenomena, as I have 

 alread}' presented it, with a few cold facts. These facts 

 would seem to negative Lauterborn's whole argument so far 

 as concerns Surirella. 



But first the Lauterborn argument must be re-stated with 

 a little more precision. For the sake of clearness, a copy of 

 the essential parts of his figure-'^ of the keel and ribs of 

 Surh-ella is on the next page shown as faithful to the original 

 as an unskilled hand could make it. The author explains 



*Hau, Kernteilung iind Bewegiing der Diatomeen. Tafel I, Fig. 9. 

 This author studied Surirella calcarata. I have lettered the copy of the 

 figure iu a differeut way froui its original. 



