172 K. MITSUKUKI : STUDIES ON 



Description : — The four specimens measured were respectively 

 18 X 4 cm., 14 X 4 cm., 15 x 4.5 cm., and 15 X 4 cm. Tentacles 

 20. Body, as viewed from above, somewhat narrowed toward the 

 posterior end. The dorsal and ventral surfaces are clearly marked 

 off from each other by a series of large papillce which project 

 laterally and make up the edge of the body. The papillse are 

 not all single, but sometimes two or more are united together, a 

 membrane going round the anterior end. The whole dorsal sur- 

 face together with the lateral papillae may be described as 

 variegated in color, presenting various shades of brown or yellowish- 

 brown, on the whole growing darker toward the posterior end in 

 all the five individuals. The dorsum is roughly divided into 

 right and left lialves by an irregular broken black line running 

 along the dorsal median part and sending out irregular branches 

 towards both sides. This line may be taken to represent the 

 median dorsal interradius, and the two halves of the dorsum 

 the lateral dorsal ambulacra. Tlie large and small papillae, 

 scattered irregularly over these halves, therefore, belong to the 

 dorsal ambulacra. These papillae are comparatively large, some 

 being more than 1 cm. in height, quite thick at the base and 

 conical in shape. Although generally single, some of them are 

 double, two starting from a common base. They are not very 

 numerous. Their tips were sometimes black, but oftener reddish- 

 brown, and the surface of all the papillae was marked by incom- 

 plete and unclosed dark rings. 



There are some strikingly characteristic points on the ventral 

 surface. The mouth is surrounded by a membrane. The general 

 color was a somewhat dark brown, but there were dark patches. 

 In one specimen there were two pairs of black patches on the 

 anterior two-thirds, while the posterior one-third was entirely 



