PLATE 115. 
Fago 
1-6. Platyceras nodosum. 473 
1 a, b, & 2. Young specimens of this species, preserving about two volutions. 
3 a, b, c. A young specimen which preserves the proper form of the shell. 
4. A larger individual. 
5. A larger specimen, preserving little more than a single volution. 
6. A larger specimen of similar character with the preceding. 
7. Platyceras subnodosum. 474 
7. View of the upper side of the spire. 
8. Platyostoma ventricosa. 469 
8. A fragment of a specimen, apparently of this species, preserving a little more than one 
volution and a part of the aperture, with the pillar-lip, which is thickened and smooth. 
