PLATE 64. 



Fig. 1. 660. 37. OuTHOCERAS UNDULATUM. ( Pag. S93.) 



1 a. A fragment of this species on a slab of slialc. 



1 b. Another fragment where tlie larulnse are nearly obsolete. 



1 c. A fragment replaced by gypsum, and preserving only the annulations. 



1 d. A fragment near the smaller extremity, showing tho laniinai but partially preserved. 



1 e. Transverse section of an imperfect and somewhat distorted specimen, showing the position of the 



siphuncle. 

 1 /. Vertical section showing the convexity of a septum. 



