ACTlNOrODOUS HOLOTHUKIOIDEA. 51 



and somewhat to our surprise, that edge reveals itself as double. 

 In f\g. h 3, a part of the surface shown in fig. Ji 1 and the 

 edge- surface are shown. This shows that the middle arch is 

 connected with the rod which passes through the axis of the 

 ellipsoid by bars (numbering three in this particular case). Fig. 

 h 4. shows the full view of the edge surface. The edge is double 

 and is pierced by a series of four holes. Fig. h 5 is the reverse 

 of that surface represented in fig. Ji 1, and shows that the arches 

 here are again irregular and in no way correspond with those of 

 the opposite side. 1 was able to obtain sections of these ellipsoids 

 by imbedding and cutting them in celloidin. Fig. k is one of 

 these sections ; it shows many features visible in fig. h. There 

 are in all seven rods which serve as supports of the ellipsoid, viz., 

 (1) the central rod, (2) a pair at each edge, and (3) one in the 

 middle of each of the two ])roader surfaces. These rods are con- 

 nected with one another by a series of cross-bars. The middle 

 rod of ea(,'li broad surface is connected with the central axial rod 

 by a series of three crossbars (see textfig. h 1 and 3). The two 

 lateral rods on each side are connected with each other by three 

 crossbars, making a series of four holes in all ; and strange to 

 say, the same rods, instead of each being connected separately with 

 the central rod, are united by a V-shaped piece with each other 

 as well as with the latter (textfig. /.■). The parts indicated with 

 dotted lines in that figure show" portions of the irregular arches 

 which connect the central rod witli the edge rods. Textfig. 

 10c/ shows the surface view of another ellipsoid. This is one of 

 those whicli. are perhaps of the most common type, the arches on 

 the surface shown being more or less regular. The middle 

 piece has a series of four more or less symmetrical open- 

 ings (shown by heavy lines) on each side. A series of four 



