PLATE CIX.— Continue. 



Pig. 10. A lateral ^^ew of the cast of a 8i)ecimen. The adhering shell preserves only the transverse striae 

 of growth in a nearly obsolete condition. This is the typical 8j)ecimen of the species described 

 by Mr. Vanuxem. It was originally nearly covered and inclosed in the grand chamber of a 

 large indindual of Goniatittt Vanitxemi. This condition of the specimen was doubtless the 

 source of the error which led to regarding this one as the larger and " more abundant " foi'm, 

 while it never reaches one-half the size of O. Vanaxemi, and is far less numerous in individuals. 

 Manlius, N. T. 



Fig. 11. A transverse section of a volution, showing the position of the siphuncle, form, etc. The sides are 

 more convex than usual, and the carinations at the umbilical angles are a little too attenuate — 

 being stronger in the original. 



Fig. 12. An enlargement of the surface, showing the continuous transverse strise and the interrupted 

 revolving striee, as appearing on the surface of the specimen fig. 9. 



