36 



K. MlTSUKUltl : STUDIES ON 



Specimens examined : — 



Description : — " Body elongate, equally rounded at each ex- 

 tremity, flattened. Mouth ventral, with twenty yellow tentacles. 

 Anus subdorsal. Dorsal surface with conical processes, few in 

 number, of equal size, the largest measuring 5 to 10 mm. in length; 

 those processes which attain a greater size are thinly placed on or 

 in the neiglibourhood of the two dorsal ambulacra, wliile the 

 smaller are to be found partly in very limited numbers scattered 

 among the larger, partly more crowded, forming a simple row 

 along the sides of the body and round its anterior extremity. The 

 pedicels probably form a double row along each lateral ventral 

 ambulacrum, but on the odd amliulacrum, marked out l)y a dee[) 

 furrow, I could not convince myself of the presence of any such 

 appendages. The calcareous ring is very reduced, in the larger 

 specimens absent. Two genital bundles, one on each side of the 

 dorsal mesentery. A single Poliaii vesicle and madreporic canal. 

 Body-wall thick, strengthened by C-shaped bodies and tables. In 

 some parts of the body the spires grow much larger, and possess 

 much more numerous transverse beams ; in others all the tables 

 become very robust, with a greater number of holes in the highly 

 dilated ends of the arms, and with the spire more irregularly 

 developed and highly spinous. As a rule, the four rods which 

 constitute the spire are almost parallel and p'l'ovided with spires. 



