1349 



pressed ; hinge well developed, anterior right lateral present, the other laterals 

 obsolete; margins rather strongly crenulate. Height 6.5, length 7.0, diameter 

 3.5 mm. 



If this species grows to a larger size it is probable that the additional sur- 

 face will be distinctly concentrically sulcate. 



Codakia (Jagonia) sp. indet. 



Oligocene of the lower bed at Alum Bluff and of the Chipola River, 

 Florida. 



Several specimens of a nepionic Jagonia distinct from any of the described 

 species and resembling the delicately sculptured forms of C. orbiculata, but 

 too young for positive identification, were obtained as stated, and another more 

 strongly sculptured from the silex beds at Ballast Point, Tampa Bay. 



Codakia (Jagonia) chipolana n. sp. 

 PLATE 52, FIGURE 9. 



Oligocene of the lower bed at Alum Bluff, of the Chipola River, Calhoun 

 County, and of Oak Grove, Santa Rosa County, Florida ; Burns. 



Shell rounded, slightly inequilateral, the posterior side shorter, moder- 

 ately convex, with small, pointed, distinct, but not elevated beaks; sculpture 

 of close-set, flattish, narrow, concentric ridges more distinct on the umbones 

 and below the middle of the disk, crossed by numerous, even, non-bifurcate, 

 radial grooves, whose interspaces are about as wide as the concentric ridges; 

 the posterior area is set off by a wide, shallow sulcus, beyond which there are 

 several radials, and the concentric sculpture becomes more or less lamellose; 

 anteriorly, too, the radials become more pronounced, and there is a small, lan- 

 ceolate anterior dorsal area; the lunule is subglobular, small, and deeply im- 

 pressed ; the hinge and marginal crenulations are strong, the anterior cardinals 

 are effaced by the lunule and the scars are normal. Height 7.5, length 8.2, 

 diameter 5.0 mm. 



The well-defined dorsal areas and stronger distal sculpture throw a doubt 

 on the proper place of this species, which in some respects recalls Lucinisca. 

 It is a well-defined form and not uncommon in the Chipola marl. 



Codakia (Jagonia) magnoliana n. sp. 



PLATE 52, FIGURE 17. 



Upper Miocene of Magnolia, Duplin County, North Carolina; Burns. 

 Shell small, thin, inequilateral, the beaks five-elevenths of the whole length 



