JOUENAL 



OF THE 



ROYAL MICROSOOPIOAL SOCIETY. 



OCTOBER 1884. 



TRANSACTIONS OF THE SOCIETY. 



XVI. — Researches on the Structure of the Cell-walls of Diatoms* 



( Continued.) 



By Dr. J. H. L. Flogel. 



(.Read 12th December, 1883.) 

 Plates IX., X., and XI. 



5. Triceratium. 



The old attempts to explain the sculpture of this group may be 

 passed over, also Prof. A. Weiss's work of 1871 (28), since we 

 have a very good paper by 0. Mtiller on Triceratium favus Ehrenb. 

 (15), which elucidates the entire sculpture of the valve in a most 

 satisfactory manner. I might therefore omit my investigation of 

 T. favus, the only species I examined, the more so as I have 

 generally only to confirm Miiller's results. As, however, Tricera- 

 tium is taken as the type for diatom sculpture generally, and 

 because in minor points I arrived at somewhat different results, I 

 prefer not to suppress my investigations which were made from 

 sections (serial preparations) and casts. The material was presented 

 to me by Herr MoUer, of Wedel. 



The production of sections perpendicular to the surface of the 

 membrane is a comparatively easy task. The large triangle can be 

 readily seen in the gum, and the knife guided accordingly. Series 

 of 1 5-20 sections can be made without difficulty. 



We have, as Miiller correctly describes, a thin basal membrane 

 adjoining the cell-lumen, and apparently quite smooth. On the 

 outer surface is a system of ordinary network mostly representing 

 hexagonal spaces, which are vertical chamber-walls. Above, these 

 lines extend to almost horizontal walls, leaving, however, for each 

 of these chambers a large round central opening. Each of the 



• The original paper la written in German, and ban been translated by Mr. 

 J. Mayall, jun. 



8er. 2.— Vol. IV. 2 Y 



