288 AKT. 7. — I. IJIMA : HEXACTTNELLIDA, IV. 



of the soft parts, had been prejiared and printed before I found 

 betler matcrinl for the study in Euplectella rnarshalli (Contrib. I). 



An idea of the arrangement of the soft parts may be obtained 

 from PL XXIII., figs. 22-24, comments upon which I consider 

 unnecessary beyond the explanations attached to them. 



The chambers measure 88,"- in average diameter. In fjivorably 

 situated parts of their small-meshed reticular wall, I have seen, 

 though faintly, choanocyte-nuclei, generally one to each of the 

 nodes, as shown in fig. 20. 



The three round or oval bodies in the lower part of the 

 figure just referred to are without dou1)t archreocytes, though at 

 the time of drawing them I was under the impression that they 

 were merely nuclei of a special sort. Small groups of the same 

 cells are also seen on the charaber-w\all in fig. 19. Occasionally 

 they were observed formiug compact masses of a quite large but 

 varying size. 



The trabecular cobweb is very extensively developed. Nuclei, 

 2-2': /' ill diameter ; usually with several nucleoli-like granules 

 within. The trabecuhe, generally very thin and filament-like, are 

 frequently expanded into films (fig. 19), especially on the dermal 

 and gastral limiting surfaces (fig. IS). The film-like parts may 

 appear as if containing irregularly branched and often ill-defined 

 fibers or streaks of condensed protoplasm ; this is evidently due 

 simply to irregularities in the thickness, or on the surfece, of 

 the film as enunciated on pp. 220-201. 



The trabecuUie of the gastral surface are pushed out, so to say, 

 by each and every proximal ray of gastralia, so as to form a little 

 cone around the latter (fig. 24). The cone may well be compared 

 to a tent, but it must not be accepted that it invariably exhibits 

 externally a membranous limiting surface. More frequently it is 



