Lover Palaeozoic Crinoids of Bohemia. 117 



Mus. 15417), show that the supposed ventral groove cuts 

 into the actual brachials either not at all or only to the 

 smallest extent, but that the markedly crescentic appearance 

 is formed by the incurving- of the adjoining interbrachials or 

 fixed pinnules (Fig. 7). This helps to explain the otherwise 



raBr- 



Fig. 7. — Scyphocrinus excavatus, var. Schlotheimi, from British Museum 

 specimen 15417. X 3 diani. Drawn by Gilbert C. Cliubb. 



a. Tertibracbs (III Br) seen from the inner side of the ray, showing their 

 relations to the supposed fixed pinnulars (pit) that occupy the 

 intersecundibrach area. The subhexagonal outlines of the latter 

 plates are much clearer in such a diagram, where only the sutures 

 are accurately represented; in a shaded drawing the linear 

 arrangement of the plates would stand out more clearly. The 

 latter effect is suggested here by thickening the lines between 

 the rows. 



h. The distal surface of the same set of tertibracbs, showing how the 

 ventral groove (v.y.) is formed by the supposed fixed pinnulars 

 (pn). Some of these, being broken, do not show the striated 

 sutural surface. 



unintelligible, and doubtless incorrect, fig. 25 on p. 90, pur- 

 porting to show some arms of Scyphocrinus decoratus. The 

 other statement alluded to is that the components of the net- 

 work are joined to the arms and to one another by articular 

 surfaces. This expression, if used in its strict morphological 

 sense, would indicate, not merely that the structures were 

 of brachial origin, but that they had not long become incor- 

 porated in the cup. Unfortunately for the argument, the 

 union, at least in the specimens at my disposal, is by loose 

 suture, with a crenelated edge and probably a striated joint- 

 surface, just like that between the primary elements of the 

 cup. On the other hand, since this is also the mode of union 

 between the fixed brachials, the pinnular origin of the net- 

 work remains undisproved. The above- quoted statement, 



