TRANSACTIONS OF WAGNER 

 1130 



TERTIARY FAUNA OF FLORIDA 



which is easily eroded and therefore apparently absent in a certain proportion 

 of specimens. The pustulation is more conspicuous on fully grown specimens, 

 and the adolescent sometimes do not have any. The outline varies somewhat, 

 not only with age but also in different individuals, and has led to the suspicion 

 that the 6". compressa may perhaps only be an extreme variation of -S\ pro- 

 texta. A single fresh valve of the latter was dredged off Cape Lookout by the 

 United States Fish Commission. 



Sportella petropolitana n. sp. 

 PLATE 45, FIGURE 10. 



Miocene marl of Petersburg, Virginia ; Burns. 



Shell small, oblong, subequilateral, moderately convex, the dorsal slopes 

 evenly arched, the base nearly straight, and the ends rounded ; beaks low and 

 inconspicuous; outer surface nearly smooth or sculptured with incremental 

 lines; hinge with the cardinal tooth single, smooth, and conical, the pit small, 

 triangular, and the ligamentary ridge obscure. Lon. 5.75, alt. 3.75, diam. 2 

 mm. 



A single small valve establishes the presence of this species at this locality. 

 From 5. constricta of the same size it can be distinguished by the even arch 

 of the dorsal margin, the thinner and more elegant shell, and the absence of 

 the posterior dorsal reflection which gives this part of the shell in 5". constricta 

 a squarish aspect. The cardinal tooth is also smaller and more slender. 



Sportella compressa H. C. Lea. 



PLATE 25, FIGURE 30. 



Petricola compressa H. C. Lea, Trans. Am. Phil. Soc., 2d Ser., ix., p. 239, pi. 34, fig. 15, 

 1845; Conrad, Proc. Acad. Nat. Sci. Phila. for 1862, p. 574, 1863; Meek, S. I. 

 Checkl. Mio. Fos. N. Am., p. 9, 1864. 

 Sportella compressa Dall, Trans. Wagn. Inst. Sci., Hi., part iv., p. 920, pi. 25, fig. 30, 1898. 



Miocene of Petersburg, Virginia, Lea ; Pliocene of the Caloosahatchie beds, 

 Florida, Dall. 



This species is much like S. protexta, but more equilateral and of more 

 ovate form. It appears to be relatively rare. 



Sportella yorkensis n. sp. 



PLATE 44, FIGURE i. 



Miocene of the York River, Virginia, near Yorktown ; Harris. 

 Shell small, subovate, slightly inequilateral, compressed ; beaks moderately 



