PLATE XI. 
rig. 
1. 
Productus brachythcerus, G. Sowerby — Interior of tlie dorsal valve 
Page. 
153 
rig. 
2. 
Product us Clarlcei, K. Etheridge — Ventral valve, seen from the front... 
15G 
Pig. 
2a. 
The same, seen in profile 
156 
rig. 
3. 
Productus I'leminyii, J. Sowerby — Ventral valve, seen from the front 
146 
rig. 
Sa. 
Ventral valve of a younger specimen, seen from the front 
... 
146 
Fig. 
4. 
Productus uudatus, Defrance — Ventral valve, seen from the front 
145 
Fig. 
5. 
Productus ftmbriatus, .1. Sowerby — Ventral valve of a young individual 
... 
149 
Fig. 
6. 
Productus aculeatus, W. Martin — Ventral valve, seen from the front... 
... 
157 
Fig. 
7. 
Stropliomenes analoya, .1. Phillips — Dorsal valve of a young individual 
161 
Fig. 
8. 
Spirifer ylaher, W. Martin — Dorsal valve, seen from the front 
... 
177 
to 
9. 
Spirifer lineatus, VV. Martin — A'entral valve, seen from the front 
... 
174 
Fig. 
10. 
Spirifer Darivinii, J. Morris — Internal cast, seen from the dorsal side 
179 j 
Fig. 
10<i. 
The same, seen from the ventral side 
179 
Fig. 
11. 
Phynchonella invcrsa, L. G. de Koninck — Internal cast, seen from the dorsal 
Fig. 
llrt. 
side 
The same, seen from the ventral side 
... 
171 
171 
Fig. 
11^-. 
,, „ front 
... 
171 
