MONOGRAPH OF JArANESE orHIUROIDEA. 



211 



lives buried in mud, as A. vacUcola does in sand, and I believe 

 that, the reduced disk scales and the numerous and thorny arm 

 spines are correlated with its mode of life. 



A'tnphiura vadicola Matsumoto.'^ 



OphionepJd/ujs phalercda : Maektanner-Tueneeetscher, Aun. K. K. 

 Naturhisi Hofmiis., II, 1887, p. 301. (Non Lyman, 1874.) 



Ampliiura vadicola : Matsumoto, Proc. Acad. Nat. »Sei. Philadelphia, 

 1915, p. 71. 



Numerous specimens ; Sakura-jima, Kagoshima Gulf. One 

 specimen ; Chintô, Korea. 



Diameter of disk 

 8 mm. Length of arms 

 260 mm. Width of arms 

 at base 1 mm., at the 

 widest part 1.3 mm. 



Disk five-lobed, with 

 indented interbrachial 



borders, covered by a soft 

 naked skin, except along 

 the abradial and inner 

 borders of the radial 

 shields, where it is covered 

 by several rows of fine, 

 imbricating scales. Kadial 

 shields large, long, pear- 

 seed -shaped ; naked part 

 two-thirds to one-half as 



Fig. 58. Amphiura vadicola. x7. (/. From above. 

 b. From below, c. Dorsal view of three arm joints 

 at about the widest part. d. Ventral view of three 

 arm joints at about the w^idest part. e. Side view 

 of three arm joints somewhat near disk. 



1) As to the interesting life mode of this ophiuran, see Prof. Mitsukuri & H.i.EA's " The 

 Ophiurian Shoal " in Annot. Zool. Japon., I, 1897, p. 68. 



