1269 



not at all sure that it might not accord better with the true relationship to 

 propose another section under Macrocallista for sulcate species and put these 

 shells there. Those which follow are typical or at least are apparently more 

 closely related to Pitaria than to anything else. 



Pitaria (Lamelliconcha) circinata Born. 

 Venus circinata Born, Test. Mus. Vind., p. 61, pi. iv., fig. 8, 1780; Dillwyn, Descr. Cat. 



Rec. Shells, i., p. 169, 1817. 

 Venus rubra Gmelin, Syst. Nat., vi., p. 3288, 1792. 



Tellina senegalensis Gmelin, op. cit., p. 3244; Wood, Gen. Conch., p. 199, 1815. 

 Venus rubescens Solander, MS., fide Dillwyn, Desc. Cat. Rec. Shells, i., p. 169. 

 Cytherea juncea Guppy, Quart. Journ. Geol. Soc. London, xxii., p. 582, pi. xxii., fig. 13, 



1866. 



Chione circinata Gabb, Geol. St. Dom., p. 250, 1873. 

 Cytherea alternata Broderip, P. Z. S., 1835, p. 45. 

 Dione circinata Deshayes, Cat. Conch. Brit. Mus., p. 77, 1853. 



Oligocene of Gatun, on the line of the Panama Canal, Colombia, R. T. 

 Hill; of Cumana, Venezuela, Guppy; Pliocene of Trinidad, West Indies, 

 Guppy ; living on both coasts of Central America and in the Antilles. 



Gabb was mistaken in doubting Reeve's location of this species at Mazatlan. 

 It is one of the very small number of Veneridcs which occur on both the At- 

 lantic and Pacific coasts of middle America, and in harmony with this excep- 

 tional distribution also occurs in the Isthmian Oligocene. I have compared 

 Guppy's type with the recent shell and find only the difference that the hinge 

 is more solid and heavy in the fossil, but such differences also occur between 

 recent specimens, and I am therefore driven to the conclusion that, so far as 

 the material at my disposition goes, there is no specific distinction to be drawn 

 between the recent and the Oligocene shells, a conclusion earlier reached by 

 Gabb, who was, however, rather given to inadvisable consolidations. 



i 



Pitaria (Lamelliconcha) astartiformis Conrad. 

 Cytherea astartiformis Conrad, Proc. Acad. Nat. Sci. Phila., iii., p. 292, 1848; Journ. 



Acad. Nat. Sci. Phila., ad Ser., i., p. 123, pi. xiii., 'fig. 13, 1848. 

 Dione astartiformis Conrad, Am. Journ. Conch., i., p. 6, 1865 ; Checkl. Eoc. Fos. N. Am., 



p. 28, 1866. 



Lower Oligocene at Vicksburg, Mississippi ; upper Oligocene of the Chipola 

 beds at Alum Bluff and on the Chipola River, Calhoun County, Florida; 

 Burns and Dall. 



