102 
Proceedings of the Royal Society 
One of the most remarkable features in the present species is the 
mdimental condition of the ventral shields of the arms ; these 
shields being much smaller than in Ophiolepis ciliata (Mill, and 
Fossil in brick-clay of the Post-pliocene age, near Dunbar, Scotland. 
Ophiolepis gracilia — (A) viewed from the dorsal side, slightly enlarged ; 
(B) ventral wall of one of the arms still more enlarged viewed from within ; 
showing the lateral shields slightly separated from one another along the 
mesial line, where the minute ventral shields are introduced between their 
angles. The apertures for the exit of the ambulacral cirri are seen near the 
outer edges of the lateral shields. 
Trosch.), where they are exceptionally small among the Ophiurid(B, 
and where the lateral shields bear only short papilliform spines 
instead of the long, highly-developed spines of 0. gracilis. It was 
