MOLLUSCA. 485 



Formation and locality. Navesink marl, near Walnford 

 (H8 1 , I48 2 ), Holmdel and Freehold (Whitfield). 

 Geographic distribution. New Jersey. 



Plicatula mullicaensis n. sp. 

 Plate LIL, Figs. 3-5. 



Description. Shell obliquely ovate. The upper valve de- 

 pressed-convex, marked by radiating costse and concentric lines 

 of growth, at the junction of which the radiating costse are pro- 

 duced into short spines. 



The dimensions of an average specimen are : total length, 30 

 mm. ; width, 22 mm. 



Remarks. This species is abundant at Mullica Hill and has 

 usually been identified as P. urticosa. It differs from that 

 species, however, in its much more regular outline and in its 

 much finer surface markings. Only the upper valves of the 

 species have been observed, but these seem to be more uniform 

 in their characters than is usual for members of this genus. 



Formation and locality. Navesink marl, Mullica Hill (169). 



Geographic distribution. New Jersey. 



Plicatula woodburyensis n. sp. 

 Plate LIT, Figs. 8-9. 



Description. Upper valve subovate in outline, only slightly 

 oblique, moderately convex on the umbo, the remainder of the 

 valve nearly flat. Marked by more or less alternating radiating 

 costse which are nearly obsolete upon the umbonal portion, be- 

 coming regularly stronger towards the margin, those in front 

 and behind the umbo curving strongly upward, the costae ele- 

 vated at intervals into small, short spines directed at nearly 

 right angles to the surface of the shell. Lower valve not known. 



The dimensions of the type specimen are: height, 28.5 mm.; 

 width, 26 mm. 



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



Geographic distribution. New Jersey. 



