PLATE 115. 



Pifa 



Fig. 1-6. Platyceras nodosum. 473 



1 a, 6, & 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. 



Fig. 7. Platyceeas subnodosdm. 474 



7. View of the upper side of the spire. 



Fig. 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. 



