48 PALEONTOLOGY OF NEW JERSEY. 



of the anterior beak, as a part of the marl has crumbled at that point, 

 but as far as the specimen showed when first obtained, the figure is cor- 

 rect and may be relied upon. The specimen is, moreover, somewhat dis- 

 torted by oblique pressure, making the under surface of the volution broader 

 and less abrupt than is natural. This corrected would cause it to resemble 

 Mr. Gabb's figure more closely. 



Formation and locality: In the dark-green, friable, and rather coarse 

 layers of the Lower Green Marl, at Holmdel, New Jersey. In the collec- 

 tion of Prof. Reiley. Mr. Gabb's specimen was from Mullica Hill, New 

 Jersey, from a similar position. 



Genus PYRIFUSUS Conrad. 



Jour. Acad. Nat. 8ci., Phila., 2d ser., vol. 3, 1858, p. 333. Type P. subdensatus, 

 ibid, p. 332, PI. xxxv, Fig. 12. 



Mr. Com-ad describes this genus, which is founded upon his species 

 Piffifiisiis suhdensatus, as follows: "Pyriform; columella broad, thick, flat- 

 tened; body volution transversely oval." Mr. Conrad's type specimen upon 

 which both the species and the genus was founded is before me, and there 

 are two of the characters as given in the above generic description that I 

 should consider as not really belonging to the shell. The statement that 

 the columella is "flattened," I should consider incorrect. It is excessively 

 thickened for the entire length of the inner lip, almost forming a tubercle 

 at the upper end, and along the narrow part of the canal is so much thick- 

 ened as to give it a sharply angular ridge on the inner edge, but there is no 

 flattening of the columella like that of Littorina or Purpurea. In this one 

 , specimen, the only one I have seen of the species, the thickening of the 

 columella with age has been so great as to raise its surface very much above 

 that of the external shell surface directly against it, in this way making 

 the entire columella much broader than it would be in a younger shell. 

 Another feature of the description above quoted is "body volution trans- 

 versely oval." Neai-ly all univalve shells having rapidly increasing volu- 

 tions appear oval in a summit view, or, as the description says, "transversely 

 oval," from the greater increas,e in diameter of the outer part of the vohi- 



