LOCOMOTION IN SURIRKLLA. 1 55 



of Surirella and in the ribs as far as clear vision of details 

 could be had. 



The protoplasm of the ribs is stained a dark indigo, and 

 seems made up of a mass of excessively minute particles, 

 interspersed with larger granules. The protoplasm within the 

 keel (PK), after staining, is quite similar, and absolutely 

 continuous with the former. Occasional still larger granules, 

 possibly the Biitschli granules, occur in ribs and keel, and not 

 alone along the base of the latter. The keel protoplasm is 

 surprisingly granular, considering its invisibility in life. It 

 occupies as a rule only about two-thirds the diameter of the 

 keel -canal, and is therefore somewhat shrunken. This also 

 has happened to the protoplasm of the ribs, as is shown at 

 the slightly contracted opening between keel and rib, where 

 the strand, though shrunken, still shows the effect of its con- 

 striction in the living state. 



While the iron-alum-haematoxylin preparations were the 

 most satisfactory, the eosin stainings also were quite conclus- 

 ive, and indeed in some cases rather preferable on account of 

 less shrinking of the protoplasm. In places this still almost 

 fills the keel-canal and remains in contact with the constricted 

 openings of the ribs. Since both stainings are from material 

 fixed at the same time, it is probable that the iron-alum ope- 

 ration had some slight shrinking action of itself, though the 

 dehydration may also have contributed. 



To sum up the facts as to the protoplasmic nature of the 

 keel-contents of Suriyella : — 



1. Biitschli granules, or bodies of the same deportment 



in life, circulate into the keel and run along its base. 



2. Staining the living diatom with Bismarck brown and 

 tannic acid fails to indicate coleoderm within the keel, though 

 revealing it in the same preparation upon Eiinotia and 

 Pinniilajia . 



3. After rapid killing and fixing, both eosin and iron- 



