TRANSACTIONS OF WAGNER 

 1 IO2 



TERTIARY FAUNA OF FLORIDA 



of Shell Creek, and of Alligator Creek, south Florida ; recent in two to fifteen 

 fathoms from Cape Lookout, North Carolina, to the West Indies and south to 

 Santa Marta, Brazil. 



This species is abundant in the West Indies and differs especially in the 

 amount of impression of the posterior area and the elevation of the upper 

 part of the posterior margin projecting from the central part of the depression 

 when the valves are closed. Some specimens have only a slight depression, 

 others have it very marked, and the intermediate stages are so common that 

 it is evident they are of little systematic value. Professor Heilprin compared, 

 as it happened, extreme specimens, which have a very different aspect without 

 the connecting gradations. 



Cardium (Fragum) arestum n. sp. 

 PLATE 40, FIGURE 10. 



Pliocene of the Caloosahatchie River, Florida. 



Shell solid, thick, elevated, rather oblique, with the anterior region very 

 short; beaks high, involute; sculpture of on the body thirty and on the 

 posterior truncation fourteen flattened ribs with very narrow channelled inter- 

 spaces, the whole crossed by extremely fine, close, concentric threads, and on 

 the body supplemented by sparse imbricating arched nodules, low and distant, 

 which towards the middle of the shell tend to stand on the posterior half 

 rather than in the middle of the ribs ; posterior truncation well marked, 

 bordered near the beaks by a sharp keel which lower down becomes obtuse; 

 interior normal, the margins fluted below the hinge. Alt. 24, Ion. 19, diam. 

 21 mm. 



This species in its form and sculpture appears to be the Pliocene representa- 

 tive of the Pacific C. planicostatum Sowerby, but differs from that species in 

 the unusual brevity and obliquity of the anterior end of the shell. In a large 

 number of specimens of C. medium both recent and fossil I have seen nothing 

 approaching it at all closely. 



Cardium (Fragum) biangulatum Sowerby. 

 Cardium biangulatum Sowerby, Zool. Journ., iv., p. 367, 1829 1 Conch. 111., Cardium, p. 7, 



pi. 46, fig. 2, 1841. 



Pliocene of San Quentin Bay, Lower California; Pleistocene of Santa 

 Barbara, California; recent in ten to twenty fathoms, Catalina Island, Cali- 

 fornia, and south to Panama. 



