TRANSACTIONS OF WAGNER 

 1048 



TERTIARY FAUNA OF FLORIDA 



the species in the Oak Grove sands is one of those items which illustrate the 

 transitional character of these sands and their faunal modification by the influx 

 of northern species of a type belonging to colder water than that of the earlier 

 Oligocene in Florida. 



Macoma Conradi n. sp. 

 PLATE 47, FIGURE 3. 



Miocene of Darlington, South Carolina; of the Natural Well and Mag- 

 nolia, Duplin County, North Carolina, and York River, Virginia ; Burns 

 and Harris. 



Shell thin, inflated, ovate, broad and rounded in front, rapidly attenuated, 

 roundly pointed and somewhat flexuous behind ; beaks low, pointed, near the 

 posterior third ; surface smooth or marked only with fine incremental lines ; 

 hinge normal, feeble, teeth small ; adductor scars large, pallial sinus short, 

 rounded, and curved (in the right valve) well backward below before coal- 

 escing with the pallial line. Lon. 22, alt. 14, diam. 7 mm. 



This is a shorter and broader and less flexuous shell than M. virginiana 

 Conrad, some of the varieties of which somewhat approach it. 



Macoma virginiana Conrad. 

 Tellina lusoria Conrad, Fos. Medial Tert, p. 35, pi. ig, fig. 3, 1840; Proc. Acad. Nat. 



Sci. Phila. for 1863, p. 573, 1864; Emmons, Geol. N. Car., p. 297, fig. 2250, 1858; 



Tuomey and Holmes, Pleioc. Fos. S. Car., p. 89, pi. 22, fig. 5. 1858; not of Say, 1822. 

 Tellina virginiana Conrad, Am. Journ. Conch., ii., p. 76, 1866; not of Clark, Bull. 141, 



U. S. Geol. Surv., p. 76, pi. 15, fig. 4, 1897. 



Miocene of York River, Petersburg, and the Nansemond River, near Suf- 

 folk, Virginia ; Pliocene of the Caloosahatchie River, Florida ; of Mrs. Guion's 

 marl-pit, Waccamaw River, South Carolina; and the north end of the Great 

 Dismal Swamp, Virginia. 



After repeated studies of the subject I have come to the conclusion that 

 Say's Psammobia lusoria was probably based on a large specimen of the shell 

 which he afterwards described under the name of Tellina tenta. From that 

 species the present shell differs, as Conrad states it does from lusoria, by being 

 higher, more arcuate below, and less compressed and flexuous behind ; it also 

 averages considerably larger. The pallial sinus is low, rather short, rounded 

 in front, and about half confluent with the pallial line below. There is some 

 doubt as to whether the shell figured by Emmons is the same, as he speaks 

 especially of sharp, elevated lines on the surface, which I have not observed 

 on any of the Virginia shells. 



