TRANSACTIONS OF WAGNER 



TERTIARY FAUNA OF FLORIDA 



striate ; ears small, subcqual, the surface coarsely radially threaded, the byssal 

 ear produced with a conspicuous sinus and fascicle; ctenolium well marked ; 

 inner basal margin fluted by the ribs ; cardinal margin with two or three 

 strong crural ridges. Alt. 40, lat. 45, diam. about 22 mm. 



This is an interesting species, peculiar from its small size and the abrupt- 

 ness of its knuckle-like undulations. Some specimens, however, are but little 

 undulated, and the mutations are much the same as occur in other species of 

 the section. 



The following species, while they are related by sculpture, form, and con- 

 chological character to the Nodipecten type, are not known to form nodules ; 

 the ribs may be slightly tumid at intervals or periodically undulated, but 

 there are no hollow bullse, as in the more typical forms. But these characters 

 are precisely those of the non-nodulous varieties of the nodulous species, and 

 so I feel justified in including them in this section. 



Pecten (Nodipecten) anatipes Morton. 



Pecten anatipes Morton, Am. Journ. Sci., xxiii., p. 293, pi. 5, fig. 4, 1833 ; Syn. Org. Rcni., 

 p. 58, 1834. 



Oligocenc of Mississippi, Vicksburgian horizon, at Heidelberg and in 

 Jasper County ; Johnson. 



The shell is small, with five or six ribs and narrower feebly striated inter- 

 spaces ; cardinal crura well developed. 



Pecten (Nodipecten) pulchricosta Meyer and Aldrich. 

 Pecten piileliricosta M. and A., Journ. Cin. Soc. N. H., ix., p. 45, pi. 2, figs. 23, 23 a, 



1886. 



Jacksonian Eocene of Wahtubbee Hills, Clarke County, Mississippi; 

 Aldrich and Burns. 



Shell small, thin, with eight large ribs, which near the umbo arc divided 

 by one or two well-marked sulci, which soon become obsolete, after which the 

 ribs are simple; the surface sculpture is of even, uniform, crowded, concentric 

 elevated lines. The ears are subequal, the byssal notch well marked. Neither 

 in Meyer's figure nor in the specimens do I find the ribs dividing near the 

 basal margin, as stated in his diagnosis. 



Pecten (Nodipecten) Rogersi Conrad. 



1'ecteti Rogers! Conrad, Journ. Acad. Nat. Sci., 1st Scr., vii., p. 151, 1834; Medial Tcrt, 

 p. 45, pi. 21, fig. 9, 1840. 



