of coNCiiOLoar. 103 



CYPRINID^E. 



VENILIA, Morton. 



This is another genus of the Chalk which characterizes the 

 Gosau deposits and the Senonien strata of North America. 

 The American species are as follows : V. Conradi. Morton, V. 

 rhomboidea, Con., V. humilis, Meek, V. Oabbana, Meek, V. sub- 

 tumida, Meek ; V. trapezoidea, Con., V. trigona, Gabb, V. La- 

 phami, Shumard sp. European species : V. cretacea ( Gypri- 

 cardia testacea, Zittel), V. bifida (Cyjirina bifida, Zittel), V. 

 crassidentata [Cyprina crassidentala, Zittel), V. cycladiformis 

 {Gyprina cycladiformis, Zittel), V. planidorsata (Isocardia plani- 

 dorsata, Zittel). A genus unknown in the Tertiary. 



CARDITID^E. 



PSEUDOCARDIA, Conrad. 



G. Smidti, Horn, C. Hungaricum, H., 0. Mageri, H., C. Ha- 

 ueri, H., C. apertum, Munster, G. conjugens, Partch., V. Neoco- 

 miensis, D'Orb., V. quadrata, D'Orb., V. tenuicostata, Zittel, V- 

 Dupiniana, D'Orb., V. constantii, D'Orb., V. cottaldina, D'Orb., 

 V. dubia, Sowerby. A genus which became extinct in the 

 Upper Cretaceous Period. 



MYTILIDvE? 



ORTHONOTA, Conrad. 



The type of this genus is 0. undulata, Con. European 

 species: Sanguinolites anguliferus, M'Coy, S. iridenoides, 

 M'Coy, S. clava, M'Coy, 0. rigida, Sowerby, 0. inornata, Phil. 

 American species : 0. undulata, Con., 0. carinata, Con. 



The genus is easily recognized by its narrow, elongated 

 form, with nearly or quite rectilinear and parallel dorsal and 

 ventral margins, and by the presence of either undulations or 

 oblique raised lines posteriorly. The shells were extremely 

 thin, apparently without cardinal teeth. 



SOLENDm 



PLECTOSOLEN, Conrad. 



Under this head I propose to group some Older Eocene 

 forms, which are straight or slightly recurved ; beaks nearly 

 terminal ; an anterior furrow direct or oblique, with a corre- 

 sponding ridge within. European species: Solen gracilis, 

 Sowerby, S. obliquus, Sowerby, S. Dixoni, Sowerby, Gultellus 

 affinis, Sowerby, S. angustus, Deshayes, S. proximus, Deshayes. 

 American species: S. protexius, Con. (Oregon.) 



