26 PROCEEDINGS OF THE ACADEMY OF [1880. 



Deducting two or three species that are also found at Eastoii, 

 we still have left twenty-three (or 68 per cent, of the whole 

 number) that are not found in the later deposits. 



Museum of the Academy fails to reveal anything answering to Conrad's 

 original description. This species appears moreover to be identical with 

 the Venus concentrica described by Tuomey and Holmes in their work on 

 the Pliocene fossils of South Carolina (1857, p. 82), and to which Conrad, 

 apparently without good reason, applied the specific name of intermedia 

 {Dosinia {Artemis] intermedia) in his check list of Miocene fossils (Proc. 

 A. N. S., 1863, p. 575). The A. acetabulum is found fossil in the tertiary 

 deposits of Maryland, Virginia, North Carolina and South Carolina, and 

 must be carefully distinguished from tlie A. concentrica of Born, to Which 

 it bears only a distant resemblance. Another fossil species is probably the 

 A. elegans, Con. (living on the Florida coast) ; one almost perfect speci- 

 men, which agrees in all essential respects with the recent forms, is in the 

 Academy Miocene collections, but, unfortunately, the locality whence it 

 was obtained is not given. In his account of the geology and organic 

 remains of the peninsula of Maryland (1830, J. A. N. S., vol. vi, p. 312), 

 Conrad mentions the Cytherea {Artemis) concentrica, Lam., as occurring in 

 the St. Mary's exposure, but as subsequently ("Fossils of the Medial 

 Tertiary," 1838, p. 30), it is distinctly stated that the same does not occur 

 in the Miocene formation, it is highly probable that the original observa- 

 tion was erroneous. Certainly nothing corresponding either to the species 

 in question or to A. discus is to be found in the Maryland Miocene collec- 

 tion of the Academy. 



The common species inhabiting the southern coast is not the A. concen- 

 trica of Born, with which it has been frequently confounded, and to which 

 it bears only a very slight resemblance, but the A. discus of Reeve {loc. cit. ). 

 A third species, the A. (Dosinia) Floridana Con., is unquestionably very 

 closely allied to the last, from which it differs essentially only in the 

 gi'eater obliquity of the pallial sinus. In other respects it agrees with the 

 figures and minute description of Born's species as given by Agassiz in his 

 '■^ Iconographie des Coquilles Tertiaires^' {JSlouv. Mem. de la Societr 

 Hehetiqtce, 1845, vol. vii). 



I am disposed to consider the various forms of Ve7ius alveata and T^ 

 latilirata as mere varieties of one and the same species, a series of inter- 

 mediate stages seeming to link them together. The V. athleta constituted 

 by Conrad to embrace the V. athleta of Say, V. latilirata of Tuomey and 

 Ilolmes, and the V. paphia of Lamarck, appears likewise to be nothing 

 but a variety of the same form. The V. alveata is included by Stimpson 

 among the living mollusca of the Atlantic coast (Smithsonian Check 

 Lists, I860;, but this fact appears very doubtful in the opinion of Try on 

 ("American Marine Conchology," 1873, p. 160). It must be confessed, 

 however, that there exists a very striking agreement between the fossil 

 shell and specimens of the F. paphia, Linn., from St. Thomas, the main 



