PLATE V. 
Fig. 1.—Carbonicola acuta (form a), showing the opposing hinge-plates of oppo- 
site valves from the Bowling Alley roof, Ivy House Colliery, Bucknall. This I 
regard as the normal form. My Collection. (Page 51.) 
Fig. 2.—Carbonicola aquilina, showing the opposite hinge-plates of oppeaee 
valves. From the same locality as above. My Collection. (Page 69.) 
Fig. 3.—Carbonicola acuta (form a). Left valve, showing hinge. Cockshead 
Rock, Hulme Colliery. My Collection. (Page 51.) 
Figs. 5—11, 13, 15, 16—Carbonicola acuta (form a). <A series of valves 
from the Cockshead Rock, Hulme Colliery, Adderley Green, showing minute 
variations in details in the hinge. My Collection. (Page 51.) 
Figs. 4 and 12. Carbonicola acuta (form a), showing the hinge, from the Ten- 
foot Coal, Bucknall. My Collection. (Page 51.) 
Fig 14.—Carbonicola acuta (form a). View in profile of a section of the valve 
through the umbones. Same locality. My Collection. (Page 51.) 
Figs. 17—34.—Carbonicola acuta (form (3). A series showing the bevelling 
of the lower edge of the hinge-plate with occasional facets, and a transverse pro- 
longation of the cardinal tooth, all with the exception of Fig. 32 from the same 
locality, this one coming from Hanley ; and Fig. 22, which is from the roof of the 
Ten-foot, Bucknall. My Collection. (Page 52.) 
Figs. 35—37.—Carbonicola acuta. A series showing the elongated cardinal 
tooth becoming bifid in the right valve. Same locality. Type y. My Collection. 
(Page 52.) 
Fig. 38.—Carbonicola ovalis. Left valve, showing a central cardinal tooth, 
with a pit anterior and posterior to it for the reception of the bifid teeth of the 
right valve. There is a faint indication of a posterior lateral tooth, also some 
pearly nodules. Same locality. My Collection. (Page 56.) 
Fig. 39.—Carbonicola acuta. Right valve, showing a trifid cardinal tooth. 
Same locality. My Collection. (Page 50.) 
