604 SYSTEMATIC PALEONTOLOGY 



seemed worthy of a name. The species differs from the other East Coast 

 forms in the obliquely produced and rather depressed outline, the low 

 flattened posteriorly dichotomoug riblets, the very large sharply differ- 

 entiated anterior ear and the absence of the posterior auricle. 



Occurrence. MONMOUTH FOKMATIOX. Brooks estate near Seat Pleas- 

 ant, Prince George's County. 



Collection. Maryland Geological Survey. 



Superfamily ANOMIACEA 

 Family ANOM1IDAE 



Genus PARANOMIA Conrad 

 [Jour. Acad. Nat. Sci., Phila., vol. iv, 1860, p. 290] 



Type. Placunanomia saffordi Conrad. 



" Inequivalve, irregular ; larger valve radiate, spinous or subspinous ; 

 lower valve flat or concave; hinge very thin and fragile, having a longi- 

 tudinal flat shelly plate extending from the apex; hinge of upper valve 

 plain, entire, extremely thin. 1 have often found fragments of this singu- 

 lar genus in the New Jersey Cretaceous beds, but never saw the hinge 

 before Mr. Safford's specimens were received from Tennessee. The 

 muscular impression is not visible on any of the many valves I have seen." 

 Conrad, 1860. 



" In 1867 Conrad described a genus Paranomia, from the Ripley group 

 (Upper Cretaceous) of Alabama, to which he referred his Placunanomia 

 saffordi (Journ. Acad. Nat. Sci., 2d ser., iv, p. 290, pi. 46, fig. 21) and the 

 Placuna scabra of Morton. The typical species is ill preserved, and the 

 beaks almost always wanting, but, from the examination of a large number 

 of specimens, it seems probable that the genus resembles Monia in its 

 external characters; the presence of a triangular chondrophore recalls 

 Anomia, but there is not sufficient evidence of a permanent foramen, the 

 musclar impressions are not preserved, and there is in the right valve, asso- 

 ciated with the single chondrophore, a pair of low, narrow crests, recalling 



Etymology: ^apd near, anomia. 



