486 RICHARD EVANS. 



different species. If, however, the largest spicules are looked 

 upon as fully developed forms, and the smallest ones as imma- 

 ture forms, the size of the normal spicule, that is the fully 

 developed form, agrees with those of Potamolepis leubnit- 

 ziae rather than with the spicules of any other Potamolepid 

 sponge. Still there is a real difference in that these spicules 

 are distinctly swollen at the ends, while those of Potamo- 

 lepis leubnitzise are not. It seems, though closely resem- 

 bling the spicules of the species mentioned above, that the 

 spicules now discussed may belong to another species. The 

 matter, however, must be left open for the present, as the 

 above feature, when considered alone, is not a sufficient reason 

 for the formation of a new species. 



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