MOLLUSCA. 589 



the anterior slope of the shell, however, each third row of 

 spinules, and near the cardinal extremity every other row, are 

 materially stronger; the same condition is probably true for the 

 posterior slope, but this has not been observed. 



Remarks. The closest ally of this species is the common shell 

 referred to C. tenuistriatum in this report, but the two species 

 differ in several respects. The radiating rows of spinules are 

 much more uniform in size on C. uniformis than on C. tenuis- 

 triatum, although upon the anterior and probably upon the pos- 

 terior lateral slope there are rows of larger and smaller spines. 

 The valves also 1 of C. uniformis are less strongly convex than 

 those of C. tenuistriatum, and they are slightly compressed 

 towards the posterior cardinal extremity and the corrugations 

 o>f the exterior are more strongly impressed upon the surface of 

 the internal casts. 



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



Geographic distribution. New Jersey. 



Cardium trillineatum n. sp. 

 Plate LXV, Fig. 20. 



Description. Form and dimensions of the shell not known, 

 but probably similar to C. tenuisfriatum. Surface of the shell 

 marked with flattened radiating costse, with interspaces about 

 equal to or a little narrower than the costse. From each fourth 

 interspace, on the central portion of the shell, arises a row of 

 laterally compressed spinules at intervals apart about equaling 

 the width of three costse and their two intervening interspaces; 

 in each of the three intervening interspaces is a row of minute 

 tubercles much smaller and much closer together than the 

 spinules, about three or three and one-half occupying the space 

 of two spinules. On the lateral slope of the type specimen one 

 space between the rows of spinules is occupied by but two rows 

 of tubercles. 



Remarks. This species is established upon a single speci- 

 men, an incomplete impression of the exterior of a shell. This 

 fragment is about 17 mm. in length, but the specimen of which 



