VERMIOLOGY. 



PLATE CXLVI. 



ECHINUS BIFORIS 

 BIFOROUS, OR TWO-HOLED ECHINUS 



Verm, Mollusca 



generic character. 



Body roundish, covered with a bony sutured crust, and generally 

 furnished with moveable spines : mouth placed beneath, consisting 

 usually of five valves. 



f Flat on both sides : the avenues resembling petals, mouth 

 central, flat, dentated ; crown with four pores. 



f Margin sinuate : surface perforated. 



SPECIFIC CHARACTER 

 AND 

 SYNONYMS. 



Base with five grooves, and ten flexuous radiate lines : near the 

 vent two oblong perforations. 



