OF CONCHOLOGY. 269 



Observation. — This small species has the sagittate ligament 

 fissure very distinct and almost as large in proportion as in M. 

 spengleri. 



M. viRaiNiANA. — PI. 22, fig. 4. 

 American Journ. of Conch. 



MULINIA, Gray. 

 M. PARiLis.— PI. 22, fig. 5. 



Description. — Triangular, equilateral, slightly ventricose ; an- 

 terior extremity subacutely rounded ; posterior hinge slope 

 very oblique, slightly convex, extremity truncated considerably 

 above the line of the base. 



Locality. — Virginia. 



ANATINID^. 



PANDORA, Lam. 



P. arenosa Con. [Pandorella Con.) is a true Pandora, and' 

 therefore the genus Pandorella is eliminated. 



P. crassa, Con., is a species of Cleidiophora, Carpenter. 



CORBULID^. 



CORBULA, Lam. 



C. CURTA. PI. 21, fig. 6, 8. 



Description. — Triangular ; height rather more than the length ; 

 summits very prominent and post-medial ; posterior extremity 

 truncated, direct ; sides flattened posteriorly, with an abruptly- 

 rounded, obscurely-ridged umbonal slope. 



Locality. — Charles Co., Md. Prof. Cope. 



The surface of the valves is somewhat disintegrated, showing 

 conspicuous lines as of growth, but it was probably finely lined,, 

 as I infer from the less worn portions of the larger valve. 



Approximates C. elevata, Con., of the Calvert Miocene, but 

 is larger, much more ventricose, shorter, and the concentric lines 

 are much finer and less distinct. 



Locality. — Charles Co., Md. Prof. Cope. 



The Miocene shells from Prof. Cope, described in this paper, 

 are part of a collection obtained in Charles Co., Md., by James 

 J. Thomas. 



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