MOLLUSCA. 521 



pah County, Mississippi, and a comparison of the New Jersey 

 specimens with the many excellent examples in the National 

 Museum at Washington, as well as with the type of the species 

 in the collection of the Philadelphia Academy of Science, has 

 demonstrated the specific identity of the specimens from the two 

 regions. 



Formation and locality. Woodbury clay, Lorillard (102); 

 Wenonah sand, near Marlboro (I3O 1 ). 



Geographic distribution. New Jersey, Mississippi 



Anatimya lata (Whitfield). 

 Plate LVIL, Fig. 13. 



1886. Pholas ? lata Whitf., Pal. N. J., vol. I (Monog. U. S. 

 G. S., vol. 9), p. 189, pi. 25, fig. 17. 



Description. "Shell large and proportionally very broad be- 

 tween dorsal and basal margins, the relative height and length 

 being about as two to three, respectively. The general outline 

 is slightly ovate, widest at the anterior end and gradually nar- 

 rowing posteriorly, the beak being a little in advance of the 

 middle and showing somewhat above the cardinal line in the 

 slightly compressed ancj somewhat crushed specimen of an in- 

 ternal cast of a left valve, the only one yet seen. Anterior and 

 posterior ends rounded, the latter one most narrowly so; basal 

 line slightly emarginate just behind the middle of its length; 

 cardinal line apparently arcuate throughout. Surface of the 

 shell, as shown on the cast, convex, with a broad sulcus passing 

 across the valve from beak to base, reaching the latter behind 

 the middle. Anterior to the sulcus the surface is radiately 

 ribbed, the rays being somewhat alternate in size over a portion 

 of the space. At the bottom of the broad sulcus there is a single 

 larger and stronger rib, which passes from the beak directly to 

 the base of the shell, which it reaches at the point of greatest 

 emargination. Posterior to this larger rib the surface is desti- 

 tute of radiating lines, the surface being marked only with broad, 

 irregular, concentric sulci, which extend over the entire surface 

 parallel to the margin of the shell." (Whitfield.) 



