PLATE LXXIII. 
(Figures 1-10, 14-19 by E. Emmons ; II by E. 15. Simpson ; 12, 13, 20 by B. P. Whitfield.) 
Figs. 
Figs. 
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Figs. 
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Genus STKICKLANDINIA, Billings. 
Page 24i). 
Stricklandinia multilirata, Whittield. 
1, 2. Ventral and dorsal views of an internal silicious cast. The figures show the short, straight 
hinge, the sharp delimitation of the cardinal reg-ion and the orbicular outline of the valves. In 
figure 1 is seen the low median groove and the apex of the filling of the spondylium ; figure 2 
shows the median fold of the brachial valve and the cast of the small but prominent muscular 
scar. 
Niagara dolomites. Near Milicaukee, Michigan. 
Stricklandinta castellana, Wliite. 
3-6. Dorsal, profile, cardinal and ventral views of a characteristic specimen; showing the nearly 
equiconvex valves, the strong, irregularly fasciculate or duplicate 'plication, and, in fig. 5, the 
cavities left by the spondylium and low median septum of the pedicle-valve. 
7. Cardinal view of a partial internal cast, the pedicle-valve being represented beneath ; showing 
the position of the spondylium and its supporting septum and the casts of the muscular im¬ 
pressions on the brachial valve. 
Niagara group. Jones county, Iowa. 
Stricklandinia deformis, Meek and Wortlicii. 
8, 9. Profile and cardinal views of an internal cast; showing the delimitation of the cardinal area of 
the pedicle-valve and the filling of the spondylium. 
10. Dorsal view of the umbonal portion of a specimen, to show the short, sti aight hinge-line and the 
subauriculate cardinal extremities. 
Niagara group. iSt. Charles, Illinois. 
Stricklandinia Gaspensis, Billings. 
11. Dorsal view of a large individual, drawn from a plaster cast of the original specimen ; showing 
the form of the shell, a portion of the cardinal area and the abundant plication of the surface. 
Upper Siliu'ian. Ga.3X)e, Nova Scotia. 
Stricklandinia Anttcostiensis, Billings. 
12. The interior of the umbonal portion of a brachial valve ; showing the short, convergent crural 
plates and the low median muscular ritlge in the bottom of the valve. 
13. A view looking into the umbonal cavity of the pedicle-valve; showing the spondylium and its 
supporting- septum. 
14. The interior of a pedicle-valve, distorted by natural growth, and showing a sharply defined car¬ 
dinal area, delthyrium and spondylium. 
Stricklandinia Davidsoni, Billings. 
15. Dorsal view of an average example ; showing its trilobed, medially elongate form. 
Anticosti group. Anticosti. 
