Astrocoenia duerdeni 
Type . Collection of Institute of Jamaica* 
The specimen that has come under my observation does not 
permit a more detailed description. The description and 
figures seem sufficient to make the species recognizable. This 
is undoubtedly the same as Duncan* a Stylo coen la emar c i at a , as a 
comparison of the above description with the notes already given 
on his original specimen will show. The Stylocoenla duerdeni 
seems to me distinct from otylocoenia emar cl at a , both from the 
descriptions of the latter and after a comparison with specimens 
of the latter in the IT. S. national Museum# The calices of 
emarclata are much larger, the maximum diameter being 3 mm. 
The usual diameter is 2.5 ram. or a little more, while in duerdenl 
the usual diameter is between 1.5 and 2 ran* , with 2 min., as a 
maximum. This makes a difference in size of almost a milli- 
meter* Although the specimen of duerdeni is worn, in places the 
surface does not appear to have lost much from attrition, so one 
can determine the depth of the calices. They are much shallower 
than in emar ci at a 
