PLATE XXX 
Figs. 1 A, B, C, D. Amphicyrtoceras laterale (Hall). A, dorsal view. 
B, lateral view. C, cross-section at base of the living chamber. D, vertical 
dorso-ventral section, exposing the siphuncle, taken at top of phragmacone. 
From Racine member of Niagaran at some Wisconsin locality. No. 634, in 
the Public Museum of Wilwaukee, Wisconsin. 
Figs. 2 A, B. Amphicyrtoceras laterale (Hall). A, ventral view. B, 
two cross-sections, one at base of living chamber, the other at base of 
specimen. From Racine, Wisconsin, in the Racine member of the Niagaran. 
Type, numbered 2119, in the American Museum of Natural History. Same 
specimen as that figured in 20th Rep. New York State Museum Nat. Hist., 
1868, pi. 18, figs. 4, 5, 6. 
