MOLLUSCA. 563 



Description. "Shell small, triangularly ovate, very transverse, 

 with very sharp, pointed, and recurved beaks, situated just within 

 the middle third of the length of the shell and nearest to the 

 anterior end. Valves flat, marked by fine concentric lines of 

 growth and a few (three or four) broad, oblique undulations of 

 the surface which pass from the posterior hinge-line forward to 

 the basal margin. There are also a few obliquely concentric 

 wrinkles on the antero-cardinal margin which extend only a short 

 distance over the disk of the valve. Along the position of the 

 posterior umbonal ridge, the surface striae are abruptly deflected 

 upward, marking the position of the ridge and defining the pos- 

 terior slope of the valve. Posterior end of the valve narrow 

 and truncate ; anterior end obtusely angular ; basal margin regu- 

 larly and broadly arcuate. Inner margin of the valves crenulate ; 

 muscular scars small and faintly marked." (Whitfield.) 



Remarks. This species has previously been known from but 

 a single locality, Haddonfield, New Jersey. It is now recognized 

 in two other localities, at Lorillard in the Wbodbury clay, the 

 same horizon as the Haddonfield specimens, and at a locality near 

 Marlboro in the Wenonah sand. The Lorillard specimens are, 

 for the most part, fragmentary, but they are usually larger than 

 those from Haddonfield, one specimen having a length of 25 mm., 

 and the broad, oblique undulations are more conspicuous. The 

 Marlboro specimens do' not grow larger than those from Haddon- 

 field and seem to lack entirely the oblique undulations. 



Formation and locality. Woodbury clay, Haddonfield (183), 

 and Lorillard (102); Wenonah sand, near Marlboro (130). 



Geographic distribution. New Jersey. 



Super-family CYRENACEA. 

 Family OYBBNIDAE. 



Genus CORBICULA Megerle. 



Corbicula annosa (Conrad). 



Plate LXIL, Figs. 1-3. 



1869. Astarte annosa Con., Am. Jour. Conch., vol. 4, p. 279, 

 pi. 20, fig. 5. 



