PALyEONTOGEAPHICAL SOCIETY. 



VOL. LXXII. 



THE PLIOCENE MOLLUSCA. 



Vol. II, Pai;t I. 

 Pages 485—65-2; Plates XLY— Lll. 



ORDOVICIAN AND SILURIAN 

 BELLEROPHONTACEA. 



Part I. 

 Pages 1—48; Plates I— VIII. 



Issued fok 1918. 



