JIG AN AD) DOIG. IE AL: 
PLACENTICERAS. 
BIG SH 14 PPP lO CEntiGenc sri IUULfLeL Cum Eelay; elit ps sea a a 
Figs. 1, 2. Two views of the inner whorls of a small specimen from the Upper 
Missouri; Coll. U. S. Nat. Mus., No. 18936. 
3. Fragment showing peculiar sculpture of the inner shell layers, probably 
from Black Hills, South Dakota; my collection. 
4. Another specimen showing similar sculpture from same collection and 
region. ‘ 
Montana group, Upper Cretaceous. 
Eig. 5. Placenticeras wviutpielan- van: tubenculatum Elyattss 2222252255252 2222222 eee 
Fig. 5. Side view of the type of the variety. 
Montana group, Upper Cretaceous; Black Hills, South Dakota; my collection. 
TGS G— Ose LeLCLGCTALUGEN USNS To ULL I Te CUD) Ley ct Ue = see a a nS 
Figs. 6, 7. Two views of the fragment on which the species is based. 
8. Part of weathered suture of same. 
Ripley formation (?), Upper Cretaceous; Mississippi (?); Coll. Acad. Nat. Sei. 
Phila. 
[Norr.—Professor Hyatt indicated that the drawings for figs. 6 and 7 were unsatisfactory 
to him, but the specimen is too imperfect to serve as the basis for a restoration ]. 
346 
