PLATE XXX. 
Zone of Aegoceras armatum. 
Fig. L Aegoceras Lkckenbyi, Wright. Lateral view, natural size. Leckenby collec- 
tion, now in the Woodwardian Museum, 
Cambridge. 
2. ■ — — — Siphonal area, showing the ribbing and 
the smallness of the tubercles. 
3. — — — Front view of the same shell. 
4. — — — Another example in the same collection. 
5. — — — Front view, showing the lobes. 
6. — — — Siphonal area, showing the ribbing and 
convexity of this area. 
7. — — — . Accurate tracing of a portion of the lobe- 
line, showing the narrowness of the siphonal 
lobe and the magnitude and complication of 
the principal lateral lobes. 
