PLATE LXXXI. 



Zone of Stephanoceras commune. 



Fig. 1. Phylloceras subcarinatum, Young and Bird. Side view. Natural size, with 



shell preserved. Whitby. 

 My collection. 



2. — — — Front view of the same do. 



3. — — — Siphonal area, with sulci and 



carina. 



4. Harpoceras radians, Beinecke. Side view, natural size. Upper Lias shale, 



East Brent Knoll, Somerset. My collec- 

 tion. 



5. — — — Siphonal area and carina. 



6. — — — Front view with carina and ribbing. 



