MONOGRAPH OF JAPANESE OPHIUROIDEA. 221 



Opldothrix marenzeUeri : Kœhleiî, Mem. Soc. Zool. Fr., XVIIT, 1904, 

 p. 103, figs. 77-78. 



Opiiioihrix hylodes : Clark, Bull. U.S. Nat, Mus., LXXV, 1911, p. 

 263, fig. 130. 



Littoral form : — Two specimens ; Tomo, Bingo. Two speci- 

 mens ; Toba, Shima. Numerous specimens ; Arai Beacli to 

 Gorgonian Cave, Misaki Marine Biological Station. Numerous 

 specimens ; entrance of the Gulf of Tokyo. 



Sublittoral form: — Eight specimens; Kagoshima Gulf; 70 

 fathoms. Five specimens ; Asami Bay, Tsushima. Numerous 

 specimens ; off Jôga-shima, Sagami Sea. One specimen ; Komi- 

 nato, Bôshû. 



In the littoral form, which may be taken as the type of this 

 species, the disk is closely and uniformly covered with thorny 

 spines. The arm spines are much widened toward the end and 

 somewhat clavate at the top. The colour of the body is very 

 variable, and may be green, blue, brown, or purple, or very 

 often variegated with combinations of these colours. The arms 

 are annulated, and there is on the dorsal side usually a longi- 

 tudinal white or light- coloured striation hemmed by two lines of 

 a darker shade, running along the enth^e length of the arm. 



In the sublittoral form, the disk is closely and uniformly 

 covered with fine tubercles bearing several thorns on the top and 

 sometimes also on the sides. In some specimens there are also a 

 few long, slender, rough spines on the dorsal surface of the disk. 

 The arm spines are slender like those of 0. koreana, and not so 

 widened towards the ends or clavate at the top as in the littoral 

 form. The colour of the body is very variable, but on the whole 

 hghter than in the littoral form. The arms are annulated, but 

 there is no distinct londtudinal striation on the dorsal surface. 



