232 K. MITSUKURI : STUDIES ON 



characteristic and elongated (toxtflg. 44a). Its segments are each 

 composed of numerous small pieces. The radialia have blunt 

 ends anteriorly, and present one median notch and two shallower 

 lateral notches. The interradialia have anteriorly a single-pointed 

 end. Posteriorly, tlie radialia have each a single prolongation 

 divided into halves by a median canal-Uke line. The calcareous 

 ring is 2.2 cm. long in No. 1094. In No. 1655, it is about half 

 as long as the body. In each of these specimens, there were 

 observed one Polian vesicle and one stone -canal. 



Calcareous deposits : — the most common form are those 

 scattered in the body wall. They are irregular perforated plates 

 of all kinds of shapes, with or without a single-pointed spire in 

 the center {h, c). The latter, may have a perforation near the 

 base, indicating that it consists genetically of two pillars or 

 columns. The bodies in question must of course be regarded 

 as tables. Most characteristic are however the calcareous bodies 

 of the pedicels. Around the end-plates, occupying the place of 

 supporting rods of otlier holothurians, are numerous pointed 

 bodies, which have vaulted bases shaped like a tripod. In the 

 tentacles are better developed tables whicli have a perfect disk 

 and a spire which shows two columns united into one near the 

 top {d). In the anterior portion of the body and in the tentacles 

 are finely built rosettes, as well as rods with enlarged and per- 

 forated ends (c). 



LocaVitij : — J;ipa,n (v. Marexzeller '81). 



