IBY DAUD) DCI 6 
TiOXONEM AU BEDA sae aise = ele saat ee eee ae ee ee eetaee tee ee eee eee ere 
Figs. 1,1 a. Anterior and posterior sides of the same shell. Natural size. 
PLEUROTOMARIA\NEVADENSIS nae 1s meee tes atstare etait alae ee eae i 
Fig. 2. Anterior view of a slightly crushed specimen that is denuded of most of the outer 
shell. 
2a. Enlargement of a piece of the outer surface of the shell, to show the peripheral 
band and surface characters. 
PLATYOSTOMA INORNATOMe sp see ye 2 = este ne oie ool sien te el oieiane eaten ere 
Figs. 3,3a. Anterior and posterior views of the cast. Natural size, 
GRINEITHIDES FOR TEOCRM ase ie are ohana oer ala weet a ole 
Fig. 4. Central portions of the head. Natural size. 
4a. Pygidium. Natural size. 
4b. Right free cheek. Natural size. 
MUCH OD ONG (G9) ONGNCACT IS era alate ea Ne 
Fig. 5,5a. Right and left valves. Natural size. 
BELEEROPHONEMATUSC UUUS emai encase eee aie iota nee ete ee eres 
Fig. 6. Dorsal view of a large specimen. A cross-section of the body-whorl of this speci- 
men is shown in the text. See plate xxiii, figs. 1, la. : 
IPFA TY GERAS HPIS Ol eae s a ere erate ee a ee ae ao lee eee leo 
Fig. 7. Dorsal view. Natural size. 
7a. View of the side denuded of the shell. Natural size, 
7b. The other side of the same specimen, preserving the outer shell. 
WW Cor overs 0H OH) IS oso Se cnowad a6 2am aooRse dooce sceceos SSog ns eS Sosa I sossses ae sosossece 
Fig. 8. Anterior view of the specimen mentioned in the text. Natural size. 
PLAT Y CRRAS(OCCIDENS= sem seat oieeesacte sista iets esos ee aie int ate tee ine ee eet 
Fig. 9. Dorsal view of a small shell, enlarged to two diameters. 
9a. Lateral view of another shell similarly enlarged. 
Page. 
258 
259 
254 
