TRANSACTIONS OF WAGNER 



808 



TERTIARY FAUNA OF FLORIDA 



genus had not been specifically characterized, though two species were de- 

 scribed under this generic name, and it was cited by Deshayes (Bull. soc. 

 geol. de Paris, t. iii.) in 1833. In 1836 Goldfuss fully characterized the genus, 

 which was founded on two fossil species. In 1835 the recent Mytilus fluviatilis 

 of Pallas (J\I. wolgcz, Chemn., xi., p. 256, fig. 2028) was almost simultaneously 

 named Dreissena (mel. Drcisscnsia) by Van Beneden and Tichogonia by Ross- 

 massler, the former having a few weeks' precedence. In 1837 appeared the 

 names Mytilina and Mytilomia Cantrainc. Jay, in 1836, used for the Danubian 

 shell the name Dythalmia danubii (Cat. Coll., p. 25) but without description. 

 There is also a large number of variants due to misprints or errors of the pen. 

 The species D. fliciiatilis (or polyinorplius of many authors) differs from 

 most of the fossils and from our American shells by the absence of the 

 secondary myophore, and is doubtless generically distinct. Being unable to 

 determine the status of Enocephahts, the -nomenclature of the American type 

 may be provisionally stated as follows : 



Genus CONGEBIA Partsch. 



Congeria Partsch, Ann. Wiener Mus., i., p. 93, 1835. 

 Mytilopsis Conrad, Proc. Acad. Nat. Sci. Phila. for June, 1857, p. 167. Type M. leiico- 



phceatus Conr. , 1831. 



Mytilus sp. Reeve, Conch. Icon., x., pi. x., 1858. 

 Praxis H. and A. Adams, Gen. Rec. Moll., ii., p. 522, Dec., 1857. 



Mytiloidcs Conrad (lapsus), Proc. Acad. Nat. Sci. Phila. for 1874, p. 2y ; not of Brogniart, 

 1822. 



Partsch specifically mentions the myophore in his diagnosis, and an ex- 

 amination of a number of his species shows that they agree in all essential 

 systematic characters with the American shells. 



Congeria leucophseata Conrad. 

 Mytilus Icucophaatus Conrad, Journ. Acad. Nat. Sci. Phila., vi., p. 263, pi. 11, fig. 13, 



1831 ; Ravenel, Cat., p. 7, 1834 ; De Kay, New York Fauna, Zool., v., p. 184, 1843. 

 Mytilopsis leticopho'attis Conr., Proc. Acad. Nat. Sci. Phila. for 1857, p. 167 ; Dull, Hull. 



U. S. Nat. Mus., No. 37, p. 40, 1889. 

 Dreissena amcricana (Recluz MS.), in Reeve, Conch. Icon., x., pi. x. (Afyti/us), fig. 43, 



Jan., 1858; Fischer, J. de Conchyl., vii., p. 131, 1858. 

 Dreissena Riisii (Dkr. MS.) Fischer, Journ. de Conchyl., vii., p. 133, 1858. 

 Dreissena leiicoplurla Tryon, Am. Mar. Conch., p. 190, pi. 40, fig. 424, 1874. 



Pleistocene of North Beach, Osprey, Florida, Dall ; recent, especially 



