MANUAL OF THE MOLLUSCA. 



Cypbimeria, Conrad, 1864. 



Type, Cytlierea excavata, Morton. Cretaceous. North 

 America. 



Shell lentiform; hinge of riglit valve broad, with a bifid 

 oblique cardinal tooth and two oblique acute anterior teeth, 

 with an intermediate pit for the reception of the tooth in the 

 opposite valve. 



DosiNiOPSis, Conrad, 1864. 



Derivation, Dosinia, a generic name, and opsis, like. 



Type, D. Meekii. Eocene. United States. 



Shell exteriorly like Dosinia. Cardinal teeth three in each 

 valve ; posterior tooth of right valve bifid ; in the left valve, 

 a thick rugose lateral tooth fitting into a cavity in the opposite 

 valve ; under the umbo is a pit ; cartilage plate granulated ; 

 pallial sinus deep and angular. 



Distribution, 3 species. Eocene. United States. 



CoNCHOCELE, Gabb. 



Type, C. disjuncta, Gabb. Miocene ? California. 



Shell irregularly quadrate, very inequilateral, angulated pos- 

 teriorly ; presenting some analogies to Edmondia, Uiiicardium, 

 and Cardiomorpha, Ligament external; hinge with a long, 

 sharp tooth running from the beaks parallel with the cardinal 

 margin, almost to the posterior end ; pallial line simple. 



AsTABTE. Subgenus, Astartella, Hall and Whitney, 1858. 

 A. vera. Coal Measures. Illinois and Indiana. The anterior 

 tooth of the right valve has a longitudinal pit in the summit. 



[Faitily Caedit^.] 

 WooDiA, Deshayes, 1860. 



Dedicated to Searles Y. Wood, a distinguished palaeontologist 

 of England. 



Example, Tellina digitaria, Linne. 



Shell smaU, rounded, equivalve, equilateral; valves closed, 

 smooth, or ornamented with oblique, curved striae ; hinge thick; 

 right valve with a single, large, median, triangular tooth, de- 

 pressed or channelled in the middle ; left valve with two narrow, 

 unequal, diverging teeth ; lateral tooth wanting or rudimentary. 

 Ligament internal, small ; muscular scars small, equal, oval or 

 ovate ; pallial line simple. 



Distribution, 1 species. Mediterranean; also fossil in the 

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