MOLLUSCA. 591 



flattened spines one to two millimeters in length, their distance 

 apart being about equal to the space occupied by two costse ; the 

 two intervening interspaces are occupied by rows of much smaller 

 tubercles a little compressed laterally, situated at intervals about 

 one-third the distance between the spines in each row. On the 

 anterior and posterior slopes O'f the shell several rows of spines 

 alternate with single rows of tubercles. The longest spines occur 

 upon the posterior cardinal slope. 



Remarks. — Because O'f their condition of preservation, much 

 confusion exists among the species oi Cm'dium in the New Jersey 

 Cretaceous faunas, and several fo-rms having the characters of 

 the subgenus Criocardium have been confused. The type of this 

 subgenus is C. diimosum, a species which was first described 

 from the Woodbury clay near Haddonfield. The specimen illus- 

 trated by Whitfield in his figure 9 may be considered as typical 

 oi the species, all his other figures, with the possible exception 

 O'f figure 13, probably representing other species. The species 

 is a rather small form and may be recognized by its nearly equi- 

 lateral, subcircular form, and by its straighter hinge-line than 

 usual. From other species having similar surface markings, it 

 may be distinguished by its narrower and rounder radiating 

 costss. Whitfield's figure 12, showing the surface markings 

 enlarged, is of another species upon which the spines in each 

 third interspace are more compressed laterally. 



Formation and locality. — Woodbury clay, near Haddonfield 

 (183), Lorillard (102), near Matawan (103); Wenonah sand, 

 near Crawf ords Corner ( 1 26^ ) ; Red Bank Sand, near Middle- 

 town (112). 



Geographic distribution. — New Jersey. 



Cardium tenuistriatum (Whitfield). 

 Plate LXV., Figs. 13-19. 



Cardiitm ewfaulensis Whitf., Pal. N. J., vol. i (Monog. 

 U. S. G. S., vol. 9), p. 132, pi. 20, figs. 18-19, not fig. 

 17. (Not C. eufaulensis Conrad.) 



