PLATE XV. 
Page. 
rig. 1. Spirifer exsuperans, L. Gr. de Koniock — Portion of the ventral valve, with the 
area ... ... ... ... ... ... ... ... ... ... 195 
Pis. la. Internal cast of the upper portion of a ventral valve ... ... ... ... 195 
Fig. lb. Interior of the same valve, drawn from a gutta-percha impression ... ... 195 
Fig. 2. Cijrtina sepfosa, J. Phillips — Portion of the dorsal valve, seen from the front... 198 
Fig. la. Portion of the ventral valve, seen in profile, and showing a part of the dental 
plates ... ... ... ... ... ... ... ... ... ... 198 
Fig. 3. Terebratula sacculus, AV. Martin, var. hastata, J. Sowerhy — Specimen of natural 
size, seen from the dorsal side ... ... ... ... ... ... ... 202 
Fig. 3a. The same, seen in profile ... ... ... ... ... ... ... ... 202 
Fig. 2b. The same, seen from the front ... ... ... ... ... ... ... 202 
Fig. 3c. Part of the surface, enlarged so as to show the foramina ... ... ... 202 
Fig. 3d. Another smaller specimen, seen from the dorsal side, and belonging to var. 
amygdada, J. D. Dana ... ... ... ... ... ... ... ... 200 
Fig. 4. Terebratula sacculus, W. Martin, var. cyvibceformis, J. Morris — Internal cast, 
seen from the dorsal side ... ... ... ... ... ... ... 201 
Fig. la. The same, seen in profile ... ... ... ... ... ... ... ... 201 
Fig. 6. Terebratula sacculus, W . — Internal cast of the ventral valve ... ... 200 
Fig. G. S caldia ? depressa,lj. G. Tl-onmedk — Left valve... ... ... ... ... 203 
Fig. Ga. Specimen, seen in profile, anterior end ... ... ... ... ... ... 203 
Fig. 7. Scaldia? lamelUfera, It, G. He ^omwcli ... ... ... ... ... ... 203 
