PLATE XXIX. 



PACE 



Fig. 1. Steapabollus umbilioatus, M. and W 362 



I a. View of the umbilicus and underside. 



1 b. Side view, showing the elevation of the spire. 



1 c. View of upper side. 



Fig. 2. Ctbtooeras? dilatatum, M. and W 389 



A specimen imperfect at both extremities, with a portion of the shell 

 removed so as to show the septa. 



Fig. 3. Nautilus sangamonbnsis, M. and "W 386 



3 a. Ventral side of internal cast of about half of one volution. 

 3 b. Side view of the same. 



3 c. Section showing the outline of the whorls and the position of the 



siphuncle. 



Fig. 4. Nautilus planoebifoemis, M. and W 386 



4 a. Side view of an imperfect cast, with the external shell removed so as to 



show the septa. 

 4 b. Profile view, in outline, of same. 

 4 c. Section showing the outline of the outer whorl, the thickness of the 



shell, and the size and position of the siphuncle. 



