21 



PRODUCTU8 luimerosus. 

 TAB. CCCXXII. 



8pec. Char. Oblong, squareish, depressed, 

 striated, spinose? or hispid? liin-e line less 

 than the width of the valve; in the larger 

 valve are two very deep cavities near the 

 beak, and a third connected with the beak ; 

 front flattish. 



As no other indications of this species than casts re^ 

 main the existence of spines and striae upon it can 

 only he inferred from the punetums which are arrano^ed 

 in irregular rows upon the cast of the larger valve • ''the 

 protuberances that correspond to those cavities which 

 are distant from the beak, are blunt cones; while that 

 -hidi filled the beak is obscurely divided into four lobt 

 and bears a slight resemblance to a head between two 

 high shoulders, as the name implies. The length rather 

 exceeds the width. "" ^icimei 



From Breden, near Derby, by favour of the lamented 



British Mineralogy, tab. 217, as an example of M.o.„e! 

 sian Limestone in which it occurs. "^ 



