625 
13 shows the dorsal side of Fig. 11 on the paranepionic whorl inside of umbilical 
perforation and just before the apex is reached. This has sutures with dorsal 
lobes and is flattened as is shown in section of the same, Fig. 14; this flattening 
also occurs in the paranepionic whorl of Fig 6. 
Figs. 15-17. Aphetoceras boreale, Hyatt, Quebec Group; Loc., Schooner’s 
Island, Newfoundland. Fig. 15, side view, and Figs. 16 and 17, sections all one- 
third reduced, showing form and absence of impressed zone. For other species of 
this genus see PI. vi. 
Figs. 18-20. Pycnoceras apertum, Hyatt, Quebec Group; Loc., Port au Port, 
Newfoundland, Fig. 18, side view, reduced one third, with apex restored. Fig. 
19, view of venter of same encrusted with dorsal shell of older volution, the 
remainder of this volution having been destroyed by erosion. This shell shows 
the contact furrow and the dorsal lobes in the sutures of older stages. Fig. 20, 
view of the part of the nepionic whorl of Fig. 18, enlarged 2 diameters, showing 
the absence of dorsal furrow and the form of the metanepionic and paranepionic 
substages of this species. The remnants of the dorsal] shell described above are 
omitted in this figure and in Fig. 18. 
PROC. AMER. PHILOS. SOC, XXXII. 143.4 4. PRINTED AuGUuST 6, 1894. 
