589 
Phyllopod or two, Hymenocavis, usurps the ascendancy, and, 
up to yesterday, was probably the most active, and therefore 
the highest, of his tribe, known in these rocks. 
Lately, Mr. David Homfray, the explorer of the Lingula 
and Tremodoc groups (Sedgwick), has struck out a still 
larger, possibly a rarer form, of the great shield bearing 
Phyllonoda. Instead of having an ample folded carapace, or 
shield, like Nebalia, it had a hollow oblong scute, to all 
appearance only slightly hollowed, after the manner of Apus. 
Three distinct ridges on the hinder border, which . is 
truncated, render it quite probable that the body, yet 
unknown, was as broad as the shield, instead of narrower, 
which is more like that of its compatriot Hymenocaris. 
