PLATE XLIV. 
(Figures 1-12, 15-19, 23, 24, 27, 28, 31, 32 by E. Emmons; 13, 14, 20-22, 25, 26, 29, 30 by R. P. WHITFIELD.) 
r. Diductor scars, 
a. Anterior adductors, 
a'. Posterior adductors. 
Genus MERISTELLA, Hall. 
Page 73. 
MeRISTELLA BELLA, Hall. 
See Plate 43. 
Fig. 1. The interior of a pedicle-valve ; showing the teeth, the deeply excavated muscular area and the 
testaceous thickening which fills the pedicle-cavity except along the median line. 
Fig. 2. The interior of the brachial valve; showing the subquadrate outline of the hinge-plate, its 
post-lateral expansions and the ante-lateral position of the crural bases. X 3. 
Fig. 3. The hinge-plate viewed in profile from the anterior margin of the brachial valve ; showing its con¬ 
cave surface, the elevation of the crui-al bases and the median supporting septum. 
Lower Helderberg group. The Helderhergs, N. Y. 
MeRISTELLA LiEVIS, Hilll. 
See Plate 43. 
Fig. 4. The hinge-plate ; showing its subtriangular form, median concavity and supporting septum. X 3. 
Lower Helderberg group. Albany county, N. Y. 
MeRISTELLA ARCUATA, H.tH. 
See Plate 43. 
Fig. 5. The hinge-plate viewed from in front; showing the dental sockets and socket-walls, elevation of 
the crural bases and the median septum. 
Lower Helderberg group. Schoharie, N. Y. 
MeRISTELLA WaLCOTTI, sp. IIOV. 
See Plate 43. 
Fig. 6. The spirals and loop, naturally preserved by incrustation of silica, and exposed by the removal 
of the pedicle-valve. The specimen is viewed from the anterior margin, and in the cavity be¬ 
tween the cones is seen the loop with its scissors-shaped branches. 
Fig. 7. The same specimen viewed from the posterior margin, and showing the position of the branches 
of the loop with reference to the ribbon of the spiral cones. 
Fig. 8. A similar preparation, to which a portion of the internal cast of the valves adheres. The speci¬ 
men is viewed from the doi’sal side and shows the form of the spiral cones and the length of the 
median septum. 
Fig. 9. An internal longitudinal view; showing the 'position and form of the loop and one of the spiral 
cones. Partially restored. 
Fig. 10. A naturally incrusted brachidium viewed from the dorsal side, and showing the prominence of 
the primary lamellae of the cones. 
Fig, 11. A similar specimen ; showing the spiral cones on the ventral side. 
Fig. 23. A view of the brachidium from the venti’al side, a portion of the cones being omitted to show the 
primary lamellae and loop. Restored. 
Fig. 32, The hinge-plate. Drawn from a gutta-percha cast. 
Oriskany sandstone. Cayuga, Ontario. 
MeRISTELLA LATA, Hall. 
Fig. 12. An internal cast of the pedicle-valve ; showing the filling of the pedicle-cavity and of the deep 
muscular impression. 
Oriskany sandstone. Albany county, N. Y. 
Legend : dp. Deltidial plates. 
p. Pedicle-cavity, 
d. Teeth. 
