TRANSACTIONS OF WAGNER 

 IO72 



TERTIARY FAUNA OF FLORIDA 



points of interest. The Eocene forms are much more like European recent 

 species, as regards the sections of the genus to which they belong, than later 

 American forms. There are at present no species of typical Cardium in the 

 American fauna, but in the Eocene and up to the end of the Oligocene such 

 forms were not uncommon. 



The curious subgenus Ethmocardium of the Cretaceous, the section Dino- 

 cardium from the Oligocene to the present fauna, and the elegantly sculp- 

 tured Trigoniocardia are of strictly American distribution both recent and 

 fossil as far as I have been able to ascertain.* Cardium and Trachycardiuiii 

 are represented in America only as fossils. We have no representatives of 

 Tropidocardium, Hemicardium, Fulvia, Discors, Corculum, Ctenocardia, 

 Lunulicardia, or Amcularium. Cerastoderma and Serripes are circumboreal ; 

 Ringicardium, Fragum, Papyridea, Lavicardium, and Protocardia are circum- 

 tropical. Unless the internal cast from the (Eocene?) Puget group of Wash- 

 ington, figured by White (U. S. Geol. Surv., Bull. No. 51, plate ix., fig. 4, 

 1889), be an exception, we have on this side of the world no examples of 

 that curious group of modified fluviatile cockles, typified by Adacna, so abun- 

 dant in the brackish water beds of southeastern Europe and the Caspian. 



The synonymy and subdivisions of this group are as follows : 



Genus CARDIUM (L.) Lamarck. 



Cardium Lam., Prodr., p. 86, 1799; Poli, Test. Utr. Sicil., iii., pp. 50, 258, 1795; Megerle, 

 Entw., p. 53, 1811. 



Cerastes + Cerastoderma Poli, op. cit., p. 258, 1795; not Cerastes Laur., 1768 (Reptilia). 



Acanthocardia Gray, List of Brit. An., p. 23, 1851 ; H. and A. Adams, Gen. Rec. Moll., 

 ii., p. 455, 1857. 



Acanthocardium Roemer, Conch. Cab. (Cardium}, ed. ii., p. 17, 1869; Monterosato, Conch. 

 Medit., p. 18, 1884. 



Cardea Conrad (MS.) Whitfield, Lam. Raritan Clays, p. 134, i885 (C. dumosum Con- 

 rad). 



Criocardium Conrad, Am. Journ. Conch., vi., p. 75, 1870 (C. dumosum Conrad). 



Eucardium Fischer, Man. Conch., p. 1037, 1887. 



Plagiocardium Cossmann, Cat. Illustr., p. 156, 1887. 



Shell variably sculptured, usually with predominantly radial ornamenta- 

 tion, usually closed or gaping but slightly, with no lunule or escutcheon ; foot 



* Since this was written I find Cardium alternatum Orbigny, from the Turonian of 

 Sainte Maure, is an Ethmocardium. 



