MOLLUSCA. 387 



near Walnford (i48 2 ), near Jacobstown (150) ; Red Bank sand, 

 Red Bank (116), Shrewsbury River (119), near Middletown 

 (112) ; Tinton beds, Beers Hill Cut, south of Keyport (i29 9 ). 



Geographic distribution. New Jersey, Georgia. Alabama, 

 Mississippi, Arkansas. 



Nemodon conradi Johnson. 

 Plate XXX., Fig. 7. 



1867. Trigonarca eufalensis Con., Am. Jour. Conch., vol. 3, 



p. 9. (Not Area eufalensis Gabb.) 

 1869. Nemodon eufaulensis Con., Am. Jour. Conch., vol. 5, p. 



97, pi. 9, fig-. 1 6. 

 1886. Nemodon eufaulensis Whitf., Pal. N. J., vol. i (Monog. 



U. S. G. S., vol. 9), p. 83, pi. 12, fig. 5 (not figs. 3-4). 

 1905. Nemodon conradi Johns., Proc. Acad. Nat. Sci. Phil. 



(i95), P- 9- 



Description. Shell subrhomboidal in outline, the dimensions 

 of a nearly complete right valve being: length, 16.8 mm.; 

 height, 9 mm. ; length of hinge-line, 12 mm. The valves mod- 

 erately convex, with the beaks somewhat incurved and situated 

 at about the anterior third of the total length of the shell, the 

 umbo produced a little beyond the hinge-line. Hinge-line 

 straight; the anterior margin making an obtuse angle with the 

 hinge-line, broadly rounding into the slightly convex ventral 

 margin, the ventral margin curving rather sharply posteriorly 

 into the obliquely subtruncate posterior margin. Umbonal ridge 

 rounded, the posterior slope rather narrow. Surface of the 

 internal cast marked by concentric and radiating lines of nearly 

 equal strength, giving it a cancellated appearance. Anterior and 

 posterior hingle-teeth both three in number, straight and nearly 

 parallel with the hingle-margin, the posterior ones being 

 slightly longer than the anterior. 



Remarks. The name N. conradi has been proposed by John- 

 son for certain shells from the Woodbury clay near Haddon- 

 field, which Conrad referred to N. eufaulensis many years ago. 

 The Haddonfield specimen referred to N. eufaulensis by Whit- 



