TRANSACTIONS OF WAGNER 

 1066 



TERTIARY FAUNA OF FLORIDA 



recent fauna, and among the fossils their, characters seem indefinitely inter- 

 changeable. The group of which Callocardia is the most conspicuous member 

 is widely separated from Isocardia by anatomical characters. None of its 

 members have yet been reported as American Tertiary fossils. 



There are very few species of Isocardia in our Tertiary. " Bucardia" veto, 

 described by Conrad from the Shark River, New Jersey, Eocene, is referred 

 to the Venerida by Whitfield and regarded as a Cretaceous species. Harris 

 (Bull. Am. Pal, i., p. 180, pi. 16, fig. 5, 1896) has described V. mediavia from 

 the Midway Eocene of Alabama and Texas; Glossus filosus Conrad (in 

 Wailes, Geol. Miss., p. 289, pi. 14, fig. 8, 1854) is a Glycymeris. The follow- 

 ing species are all the others yet discovered : 



Isocardia floridana n. sp. 

 PLATE 46, FIGURES 21, 26. 



Vicksburgian Oligocene of Arredondo, Florida. 



Shell short, high, with strongly involute beaks, solid, strongly and sharply 

 unicarinate; inequilateral, the anterior end shorter, hardly extending farther 

 than the vertical of the beaks; base rounded from the anterior end to the 

 end of the carina, which extends from the beaks to the posterior basal angle ; 

 posterior dorsal margin gently arcuate, posterior end truncate from the end of 

 the hinge-line to the basal end of the carina ; teeth of the hinge normal, much 

 compressed, the lateral low and distant; posterior dorsal slope excavated. 

 Lon. 30, alt. 25, diam. 30 mm. 



A single cast of the inside of a right valve of this species is all that was 

 obtained, but the characters are well exhibited, except the external sculpture, 

 which may have been somewhat undulated. It cannot be any of the described 

 species. 



Isocardia fraterna Say. 



Isocardia fraterna Say, Journ. Acad. Nat. Sci. Phila., iv., p. 143, pi. xi., fig. i a-b, 1824. 

 <C Isocardia rustica Conrad, Fos. Medial Tert., p. 20, pi. xi., fig. i, 1838; not Venus 



(= Arctica) rustica Sowerby, 1818. 



Glossus rusticus Conrad, Proc. Acad. Nat. Sci. Phila., vii., p. 29, 1854. 

 Isocardia Conradi Orbigny, Prodr. Pal., iii., p. 121, 1852. 

 Glossus fraterna Meek, S. I. Miocene Checkl., p. 8, 1864. 

 Bucardia fraterna Conrad, Proc. Acad. Nat. Sci. Phila. for 1862, p. 576, 1863. 



Miocene of Maryland at Plum Point (Burns, lower bed), Charlotte 

 Hall, and St. Mary's on the Patuxent ; City Point, James River, and near 



