PLATE 49. 
Legend: VA. Cardinal area (pedicle-valve), t. Teeth. 
d. Spondylium. hp. Hinge-plate. 
s. Median septum (pedicle-valve). o. Cast of visceral foramen. 
s'. Septa (brachial valve.) 
STRICKLANDINIA, Birires. 
Page 847. 
STRICKLANDINIA CASTELLANA, White. 
Figs. 1-3, 5. Dorsal, ventral, profile and cardinal views of a characteristic 
specimen; showing the nearly equiconvex valves, the strong, irregu- 
larly fasciculate or duplicate plication, and, in fig. 5, the cavities 
left by the spondylium and low median septum of the pedicle-valve. 
Niagara group. Jones county, Iowa. 
STICKLANDINIA, sp. 
Fig. 4. An internal cast of the pedicle-valve; showing the well-defined 
cardinal area. 
Niagara group. Hamilton, Ontario. 
SrRICKLANDINIA AnticostrEnsis, Billings. 
Fig. 6. A view looking into the umbonal cavity of the pedicle-valve; showing 
the spondylium and its supporting septum. 
Fig. 7. The interior of a pedicle-valve, distorted by natural growth, and show- 
ing a sharply-defined cardinal area, delthyrium and spondylium. 
Anticosti group. Anticosti. 
AMPHIGENTA, Hatt and Wuarrtriexp. 
Page 848. 
AMPHIGENIA ELONGATA, Vanuxem. 
Fig. 8. The interior of the umbonal portion of a pedicle-valve; showing 
vascular sinuses on the surface of the valve beneath the spondylium. 
Corniferous limestone. From the drift of southern Michigan. 
Fig. 9. The interior of the umbonal portion of the pedicle-valve; showing the 
teeth and the entire spondylium. 
Corniferous limestone. Le Roy, N. Y. 
Fig. 10. Profile view of a portion of the brachial valve somewhat enlarged 
to show the direction and extent of the crura, jugal apophyses and 
crural plates. 
Fig. 11. Dorsal view of a partial cast; showing the muscular ‘impressions and 
vascular sinuses of the brachial valve, and the cavity left by the 
medially divided hinge-plate. 
Corniferous limestone. Clarence, N. Y. 
256 
