Smithsonian Report, 1936- Conger 



PLATE 3 





TnnfT \ nierp of the '^hell of Aulacodisciis margarh^ceus Ralfs (lower) with portion cut away, showing 

 L/jpc/, -T. I. porous nature and double wall structure. . _, , , . . 



Center Sections (edge view) through shell of Aulacoiisc, margaritaceus Ralfs, showing double structure, 

 ' connecting walls a-ul poYCE. 



Lower, Valve view ol Aulacodiscus margaritacex,', Ralfs. X ISO. 



