PLATE XXXI 
Fig. 1. Charactoceras baeri (Meek and Worthen). Lateral view. See 
also plate XXXII, figs, lA, B. From vicinity of Oxford, Ohio, in the basal 
part of the Whitewater member of the Richmond. Collected by Prof. W. H. 
Shideler, of Miami University. 
Figs. 2 A, B, C, D. Tripteroceras hastatum (Billings). A, ventral side, 
exposing the siphuncle. B, view of upper end, showing passage of siphuncle 
through septum. C, diagrammatic lateral view, showing the lateral saddles. 
D, diagram showing relative depth of dorsal and ventral lobes of the 
sutures. From Pauquette Rapids, in Ottawa River, Canada, in the Leray 
member of the Black River. Selected type, numbered 1281, in the Victoria 
Memorial Museum at Ottawa, Canada. 
Figs. 3 A, B, C, D. Tripteroceras pauqiiettense Foerste. A, lateral view. 
B, ventral view. C, diagram showing relative depth of dorsal and ventral 
lobes of sutures. D, cross-section at top of specimen, showing passage of 
siphuncle through septum. Part of the type series of Tripteroceras hasta- 
tum (Billings), numbered 1281 d, in the Victoria Memorial Museum, at 
Ottawa, Canada. Selected here as type of new species. 
