456 SYSTEMATIC PALEONTOLOGY 



Description. — " Flustrella concentrica, microscopica cellularum 

 minutissimarum laevium seriebiis concentricis, interdum spiralibus, 

 apertura singularuin parva rotunda." Ehrenberg, 1838. 



" All rings of the disk circular, concentric of equal breadth, con- 

 nected by numerous piercing radial beams. Chambers different in size, 

 increasing from the center towards periphery. Pores regular, circular, 

 one and a half to two on the breadth of each ring. 



"Dimensions. — Diameter of the disk (with eight rings) 0.16; breadth 

 of each ring 0.01 ; pores 0.003. 



"Habitat. — Fossil in many Tertiary rocks — Barbados, Sicily, Greece, 

 etc." Haeckel, 1887. 



Occurrence. — Calvert Formation. Popes Creek, Plum Point, 

 Lyons Creek. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 Eev. Edward Huber. 



Family PHACODISCIDA. 



Genus PHACODISCUS Haeckel. 



Phacodiscus calvertanus n. sp. 



Plate CXXX, Fig. 17. 



Description. — Disk rather smooth, three times as broad as the outer 

 and seven times as broad as the inner medullary shell; ])ores regularly 

 circular, three or four times as broad as the bars; margin of the disk 

 rounded. 



Occurrence. — Calvert Formation. Lyons Creek. 



Collection. — Maryland Geological Survey. 



Superfamily PRUNOIDEA. 

 Family CYPHINIDA. 



Genus CANNARTIDIUM Haeckel. 



Cannartidium sp. 



Plate CXXX, Fig. 18. 



Description. — The specimen on Avhich the accompanying figure was 

 based and which was intended to l^e used as the type of a new species of 



