CEPHALOPODA OF THE CRETACEOUS MARLS. 273 



was coiled like the interior of a Scaphite or Ammonite, as I had one, having 

 the septa of a Ptychoceras, which was so coiled, but which was destroyed 

 accidentally before it could be figured. If I am correct in referring that 

 specimen to one of the species of Ptychoceras, there described and figured (See 

 p. 457, PI. 16, Fig. 1), that one certainly would have been generically dis- 

 tinct from the types of Ptychoceras and would probably prove congeneric 

 with Dr. Morton's species could better specimens be procured. Conse- 

 quently I think it best to retain Mr. Conrad's name for forms like that which 

 I described and figured as above cited under the names Ptychoceras Meek- 

 anum and P. crassum. In this case the generic diagnosis of Solenoceras would 

 have to be changed somewhat as follows : 



SOLENOCERAS (as amended). 



Embryonic portions probably coiled forming one or more turns, beyond 

 which the tube is deflected in a more or less direct line, or slightly bent to 

 the end of the septate portion of the adult shell; terminal chamber recm-ved 

 upon the septate portion, which it more or less embraces, the aperture may 

 again be deflected from a right line where the younger parts are bent. 



Genus PTYCHOCERAS D'Orb. ; Solenoceras Conrad. 



Ptychoceras (Solenoceeas) annulifer. 



Plate XLV, Figs. 6-8. 



Hamites annulifer Morton: Jour. Acad. Nat. Sci., PMla., 1st ser., vol. 8, p. 213, 



PL XI, Fig. 4 ; Extract, p. 9, PL ii, Fig. 4. 

 Solenoceras annulifer (Mort.) Conrad: Jour. Acad. Nat. Sci., Phila., 3d ser., vol. 



4, p. 284; Gabb, Synopsis, p. 33; Meek, Geol. Surv. N. J., 1868, p. 730. 

 Ptychoceras (Solenoceras) annulifer (Morton) Meek: Check List Cret., p. 23. 



Shell small, known only from an internal cast of the chamber of habi- 

 tation, which is rather less than a fourth of an inch in its greatest diameter, 

 and only seven-eighths of an inch in length. The earlier portion of the 

 shell appears to have been transversely elliptical in section, as it has left a 

 broadly concave depressed area on the inner face of the outer chamber, 

 which has a curvature very much greater than that of the outer face. Outer 

 chamber contracted very slightly in diameter for a little more than the outer 

 MON xviii 18 



