TRANSACTIONS OF WAGNER 

 I178 



TERTIARY FAUNA OF FLORIDA 



Superfamily LUCINACEA. 

 Family DIPLODONTID^E. 

 Genus DIPLODONTA Brown. 



Diplodonta Brown, Ital. Tertiiir. geb., p. ix., 1831. Type Venus lupinus Brocchi; not 



Diplodon Spix, 1827. 

 Mysia Brown, Zool. Textb., p. 454, pi. 90, fig. 6, 1833; Shy. Man., p. 197, 1842; not of 



Leach in Lam., 1818, nor of Brown, 111. Conch. Gt. Brit., ist ed., pi. 17, figs, i, 2, 1827; 



not Mysca Billborg, Insecta, 1820. 

 Mysia Conrad, Fos. Medial Tert., p. 30, 1838 ; not of Leach. 

 Egeria Lea. Contr. Geol., p. 49, 1833, ex parte ; not of Roissy, 1805. 

 Sphcerella Conrad, Fos. Medial Tert., p. 17, 1838. Type S. subvexa Conrad, op. cit., pi. 



10, fig. 2. 

 TFelania Recluz, Journ. de Conchyl., ii., p. 69, 1851. Type Venus diaphana Gmelin 



{Le Felan Adanson). 

 Giocomene Leach, Moll. Gt. Brit., p. 313, 1852. 

 Cycladicama Val., Voy. au Pole Sud., v., p. 116, 1854; Fischer, Journ. de Conchyl., viii.. 



P- 377! i860. Type C. Incmiformis Val., op. cit., pi. 3, fig. 3. 

 Mittrea Gray, Fig. Moll. An., v., p. 35, 1857; sole ex. Diplodonta brasilicnsis Mittre, 



Journ. de Conchyl., i., p. 240, 1850. 

 Diplodonta + Mysia Cossmann, Cat. 111., ii., p. 21, 1887. 



This genus dates from the Cretaceous, and, considering the simpHcity of 

 its characters, seems to have received less attention than it deserves from 

 modern writers. I have shown elsewhere that Mysia Leach is based on Ltici- 

 nopsis undata, and that to the true Diplodonta Leach applied the name of 

 Giocomene. 



Conrad, Brown, and other writers have used Mysia for this genus so fre- 

 quently that much confusion has resulted. 



Egeria Lea was preoccupied when used by him and also contained repre- 

 sentatives of several genera, a few of which belong to Diplodonta. Gray 

 (Fig. Moll. An., v., p. 18, 1857) and Woodward (Man., p. 474) figure a 

 bivalve from the Philippines, perhaps a Joannisiella, which has two siphonal 

 openings and a compressed foot of the ordinary type, under the name of Mysia, 

 and therefore separated the true Diplodontas, which have only an anal siphonal 

 aperture and long Lucinoid foot, under the name of Mittrea, with Diplodonta 

 brasiiiensis Mittre as the type. This error has been transferred to Fischer's 

 Manual by inadvertence. 



An examination of a specimen of Fclania diaphana (Gmel.) Recluz dis- 

 closes some errors in his description of its characters. There is both a liga- 



