E. MARSHALLI. — FLAGELLATED CHAMBER. 139 



time after the flagella had become known to me, although sub- 

 sequent experience has proved that I had really that structure 

 under my observation. F. E. Schulze's paper ' Zur Histologie 

 der Hexactinelliden ' ('99a) gave me fresh encouragement to 

 renew my investigations into the matter, and for this purpose I 

 went once again to Dôketsba in the spring of last year, in order 

 to obtain a new supply of E. marshalli preserved in a number 

 of ways. As before, corrosive sublimate as the fixing reagent 

 gave the best results ; and a careful search on sections stained 

 "with acid-fuchsin, using a very high power (Zeiss' homogene 

 Immersion), resulted in convincing me of the indubitable presence 

 of a collar to each cell. Having once become acquainted with 

 its appearance, I found that it w^as visible in nearly equal clear- 

 ness in many of my old preparations colored with borax-carmine. 

 In order to see them well, the collars must be seen in the profile. 

 The section should be neither too thick nor too thin ; in the 

 latter case it is difficult to recognize the chamber-w^all itself. 

 Moreover, the section of the wall must be so favorably situated 

 that the collars and the flagella stand out in a perfectly clear 

 light, which should not be tinted by the colored light diffused 

 from neighboring parts lying out of the focus. I have never 

 succeeded in perceiving the collars in optical section on the 

 surface-view of the chamber-wall, the difl'use colored light coming 

 from the reticular beams and nodes being sufficient to conceal 

 them. 



The collar (figs. 40-42) in the profile view appears as a 

 narrow sheath around the base of each flagellum. It is exceedingly 

 delicate, quite clear and very faintly colored by acid-fuchsin. 

 The lateral contour-line is fine or moderately sharp ; the distal 

 edge-line, always very fine. The shape is variable, apparently 



