MOLLUSCA. 825 



1876. Scaphites nodosus Meek, Rep. Inv., Cret. and Ter. Foss. 



Up. Mo., p. 426, 428, 429, pi. 25, figs. la-c, pi. 25, figs. 



3 a-c, 2 a-c, 4, pi. 26, figs, i a-c. 

 1880. Scaphites nodosus Whitf., Geol. Black Hills, p. 441, pi. 



13, fig. 12. 

 1892. Scaphites nodosus Whitf., Pal. N. J., vol. 2 (Monog. U. 



S. G. S., vol. 18), p. 261, pi. 44, figs. 13-14. 



1898. Scaphites iwdosus var brevis Logan, Univ. Geol. Surv. 



Kas., vol. 4, p. 511, pi. 108, fig. 3. 



1899. Scaphites nodosus Logan, Field Col. Mus., Pub. 36, Geol. 



Ser., vol. i, p. 209, pi. 22, fig. 2. 



1905. Scaphites nodosus var. brevis Smith, Jour. Geol., vol. 13, 

 p. 640. 



Description. Shell subovate in general outline, the last volu- 

 tion becoming somewhat free from the inner ones in its outer 

 half, the living chamber ventricose. Sides of the shell somewhat 

 flattened, curving inward to the umbilicus, the venter broad, 

 more or less convex, the cross-section often somewhat quad- 

 rangular ; on either side of the shell, at the margins of the con- 

 vex venter, there is a conspicuous row of rounded or somewhat 

 compressed nodes ; toward the umbilical margin there is a second 

 row of tubercles on each side which are smaller than those of 

 the outer row; across the venter, between the two outer rows of 

 tubercles the surface of the shell is marked by a series of regu- 

 lar transverse ribs whose distance apart is usually one-third or 

 one- fourth the distance between the tubercles ; upon the sides 

 of the adult shell the ventral ribs do not continue, but the surface 

 is marked by much coarser, more or less indistinct ribs joining 

 the outer and inner rows of tubercles; these ribs also continue 

 somewhat down the umbilical slope. 



Remarks. The New Jersey specimens which have been iden- 

 tified as S. nodosus are all extremely fragmentary, and if they 

 were more perfectly preserved it is possible that they might be 

 found to represent a distinct species. The best example seen, 

 so far as it is preserved, agrees very well in general form with 

 Owen's type specimen of S. nodosus, which is preserved in the 



