176 I. IJIMA : HEXACTINELLIDA. I. 



involve tlie nutritive state, local or otherwise, of the soft 

 parts. 



It now remains to give notes on the thesocytes of E. mar- 

 shcdli based on my own observations of them, which liave been 

 chiefly made on those composing the orange-yellow spots. 



While some of these cells are but little larger than archieo- 

 cytes, the majority measure about 7// across, sometimes as much 

 as 12/'«. When liberated from their mass in the fresh state, 

 the cells are spherical in shape. A membranous envelope is 

 apparently wanting. The nucleus, which differs in no way 

 from that of archœocytes or of the trabeculœ, is always easily 

 demonstrable by staining (PI. IV, figs. 24, 25). 



The fat-like spherules inclosed in the cell-body are present 

 sometimes in quite small numbeis but in most cases tolerably 

 numerously, pressing the finely granular protoplasm into a tliin 

 enveloping layer and into fine partitions between them. They are 

 of various sizes within the same cell. During the teasing they 

 are easily freed from the cells. Under the microscope, the 

 single spherules appear pale-yellowisli, perfectly homogeneous and 

 moderately refractive. They are not firm solids but are evidently 

 of a soft, perhaps even fluid, nature, to judge from the manner in 

 which they change form or fuse together when subjected to 

 pressure under the cover-glass. 



In the fresh condition, the spherules can not be colored at 

 all or bnt very faintly by eosin, acid-fuchsin, Bleu-de-Lyon or 

 methyl-green. However, they greedily take up methyl-blue. 

 Iodine renders them brown, which color grows simply darker on 

 the addition of sulphuric acid. Osmic acid blackens the orange- 

 yellow spots made up of the thesocytes ; but when the latter are 

 examined singly under the microscope, the inclosed spherules or 



