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K. MITSÜKUEI : STUDIES ON 



0.052—0.060 mm. or more (c). The 

 spire is often absent or is represented 

 merely by four knobs. When present 

 it is rarely formed of five columns ; 

 about 0.035 mm. high, with one cross- 

 beam and twelve or more points, ex- 

 panded above. I can not discover any 

 conical tables. (ii) C-shaped bodies 

 numerous, usually small, measur- 

 ing about 0.032—0.36 mm. (d). (iii) 

 Rosettes not numerous but not rare ( / ), 

 not much smaller than C-shaped bodies, 

 and some at least formed apparently 

 by combinations of the latter (e). Sup- 

 porting rods in pedicels 0.4 mm. or 

 more (g). 



Size of body up to 10 cm. in al- 

 cohol. Color uniformly light brown in 

 alcohol. Skin soft and flaccid. 

 EemarJxS : — This species is nearest to Stichopus liorrens Se- 

 LENKA, from which it differs only in two points : (1) in having 

 18 tentacles instead of 20, and (2) in the calcareous deposits. In 

 S. liorrens C-shaped bodies are 0.1 mm. long, and tables are of 

 three kinds : (a) ordinary delicate ones, (b) similar but larger 

 ones distributed among (a) at regular intervals, and (c) large 

 conical ones. Whereas, in the present species I can find only 

 two kinds : (a) ordinary kind and (b) larger disked ones, mostly 

 with imperfect spires and found in ventral pedicels, especial- 

 ly near the end-disks. Conical tables can not be found. C-shaped 

 bodies are much smaller than in S. liorrens. 



Textfig. 28. 



Stichopiis hirotai : a, h — Tables 

 of perisome ; c — Same of pedicel ; 

 d — C-shaped body ; e, /—Rosettes ; 

 <j — Supporting rod. (a— /x 320 ; 

 g X 240). 



