88 I. IJIMA : HEXACTINELLIDA. I. 



ness of the tissues. In specimens preserved in weak formalin, 

 the color has likewise disappeared but the spots remain distin- 

 guishable, being more opaque than the surrounding tissues. 

 Osmic acid has blackened the spots. I think the coloring matter 

 referred to, which is combined with oil-like spherules contained 

 in the cells composing the spots, is the same as that which is 

 diffused in the soft tissues and gives to these the before men- 

 tioned pinkish-buff color. The cells of the spots will find further 

 treatment under the histology of the soft parts. (See anon 

 under Thesocytes). 



General Characters of Nearly or Quite Full-Grown 



Specimens. 



The body may be described as a gently bellied tube with 

 an irregularly corrugated external surface (PI. III). The sieve- 

 plate is strongly arched ; the basal tuft, large and elongate. The 

 broadest part of the body is usually, but not always, situated some- 

 what below the middle; so that, the general shape is frequently 

 not unlike that of a lamp-chimney, while in others it more 

 resembles a barrel or a cucumber. Young specimens show a 

 shape approaching that of a spindle. The cross-section is on 

 the whole circular, except at the extreme lower end which is as 

 a rule more or less distinctly compressed. The following are 

 measurements of some of the larger specimens taken up at 

 random : 



