52 K. MlïSUKUlil : STUDIES ON 



crossbars (shown by faint circlos) connects it with the central rod. 

 The edge pieces are connected with the axis by five crossbars 

 which are in the level of the openings of the upper surface. The 

 openings between these crossbars are therefore alternate with 

 those of the upper surface. Textfig. li)b is one of those which are 

 very irregular. Texttigs. 10 c and cl show the edge of two different 

 ellipsoids. In the textfig. 10 cl there is a departure from the common 

 type in that the openings in the middle are paired instead of all lieing 

 single. Textfigs. 10 c — g are from an individual which shows many 

 of the ellipsoids to be of a very simple structure. Here we have 

 to do with ordinary buttons with ridges on the middle piece. In 

 e, there are two such ridges and from one of them an arch goes 

 over to one side. Such cases seem to show tliat the ellipsoids 

 are derived from buttons, but exactly how these are modified, 

 it is liard to say. It seems probable that the middle piece of the 

 button becomes the central rod of the ellipsoid. On each side of 

 the middle piece ridges, or rather series of arches, are raised ; 

 then these are connected by lateral pieces with the edges. So 

 far it seems very plain ; but how the double edges of the ellipsoid 

 are formed is not quite clear. If the edges of the cross-pieces 

 unite with each other and form an edge on each side of the 

 original l.)utton, there should be two series of openings instead 

 of one. It is possible that at first they are double and afterward 

 run together into one in the middle. The two paired openings on 

 the edge, shown in textfig. 10 d, seem to point in this direction. 



This species is also cured for the market and exported to China. 

 In the prepared state there seem to Ije two varieties, probably 

 due to the differences in the color of the living animal. They 

 are known under the names of " Shiro-Usfi" (PI. III., fig. 23) and 

 " Kuro-Usa " (PI. 111., fig. 24). Their value seems to range from 



