of a Species of Echinus. 77 
Holland, to which it would be extremely difficult, if not impos- 
sible, to assign characters capable of distinguishing it from our 
common E. esculentus. 
It may be proper to add, that the species which perforates 
the rocks of the western coasts of Ireland has not hitherto been 
described as an inhabitant of the British isles. 
IV. A Com- 
