HYALONEMA (PRIONEMA) AGUJANUM. 



261 



either parallel, or slightly convergent or divergent. The teeth have the usual 

 T-shaped transverse section. Their upper (outer) band-shaped part arises 

 from the margin of a transverse circular disc situated at the end of the shaft. 

 The diameter of this disc is a little less than a third of the anchor-breadth. In 

 apical views of the anchors, the basal parts of adjacent teeth appear connected 

 by the interdental parts of this disc as by a web (Plate 77, fig. 10). The upper 

 band-shaped part of the teeth is 22-27 ^ broad at the base and in the middle. 

 It is attenuated distally and pointed at the end. The contour of the tip of the 

 tooth has the shape of a gothic arch (Plate 73, figs. 1-3; Plate 77, fig. 9). 



The macramphidiscs have on the whole narrower anchors and attain a 

 considerably larger size in var. tenuis, form A, than in var. tenuis, form B, and 

 in ^■ar. lata. Their dimensions are as follows: — 



NORMAL MACRAMPHIDISCS. 



