Mancliesier Meuioirs, Vol. h. {igw), No. 1.%. ii 



the umbonal region the anterior and posterior parts of 

 the line meet at an acute angle and form a V, the anterior 

 limb of which is approximately concentric. A similar bend 



Fig. ?>l). 



SliDwing the apparently double set of ornament in T. dicdalca. 



Fig. Sc". 



Showing the cause of tlie development of the second set of ornament 



on r. dtrdalta. 



is seen in the enlarged umbo in Fig. %b. This accounts 

 for the curious bent ornament in the upper umbonal 

 region of dcsdalea. 



About the fourth row down occurs an apparently 

 second set of ornament, running about at right angles to 

 the up-turned anterior limbs of the diagonals. 



