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beak deep and very distinct. The hinge line is rather 
shorter than the shell is wide and is not very deep. The 
roundness of the spaces between the sulci and the blunt- 
ness of the edges give a kind of plumpness to the general 
contour from which it is named. 
P. O’Kelly, Esq, has favoured me with several speci- 
mens of this Spirifer from the Black Rock, Ireland. It 
is a very distinct and apparently new species. 
