MOLLUSCA. 379 



species are from the Tinton beds, but they have a much smaller 

 number of teeth than that given by Whitfield. 



Formation and locality. Navesink marl, Freehold (Whit- 

 field). 



Geographic distribution. New Jersey. 



Leda tintonensis n. sp. 

 Plate XXIX., Figs. 31-34. 



Description. Shell small, the dimensions of an internal cast 

 being: length 10 mm., height 5 mm., convexity 1.5 mm. Beaks 

 rather prominent, nearly erect or pointed slightly backward, sit- 

 uated a little over two-fifths of the length of the shell from the 

 anterior extremity. Anterior portion of the shell semielliptical 

 in outline; posterior portion subcuneate behind; the postero- 

 dorsal margin nearly straight or slightly concave; the posterior 

 margin curving downward and forward into the basal margin 

 so that the whole ventral margin from the posterior extremity 

 of the hinge-line to the middle of the anterior margin, describes 

 nearly the arc of a circle. Anterior series of teeth straight or 

 slightly convex, about 10 or 12 in number; posterior series 

 nearly straight or slightly concave, about 15 or 16 in number. 

 Surface of casts smooth, external surface of shell unknown. 



Remarks. In general form and size this little shell agrees with 

 Whitfield's illustration of the type of his Leda gabbana, but it 

 differs from that species according to 'the description, in having 

 much coarser teeth, there being 25 posterior and 20 anterior 

 teeth in that species, which is nearly twice as many as in the shell 

 under discussion. 



Formation and locality. Tinton beds, Beers Hill cut, south 

 of Keyport (i29 5 ). 



Geographic distribution. New Jersey. 



Genus PERRISONOTA Conrad. 



Perrisonota protexta Conrad. 

 Plate XXX., Figs. 1-2. 



1869. Perrisonota protexta Con., Am. Jour. Conch., vol. 5, p. 

 98, pi. 9, fig. 24. 



