BRACHIOPODA. 
66 
the beaks of both valves, produces a “shouldered” appearance. There is a low 
sinus on the pedicle-valve which is apparent only over the pallial region; this 
is accompanied by a slight fold on the opposite valve. The apex of the pedicle- 
valve is closely incurved, concealing both deltidium and foramen. On the 
interior the teeth are moderately prominent and are supported by strong dental 
plates, which not only extend to the bottom of the valve, but are continued 
forward for about one-third the length of the shell, and inclose a narrow, 
elongate muscular area.* In the brachial valve the hinge-plate appears to be 
short and constructed on the same plan as that of Meristina and Whitfield- 
ELLA, with two diverging crural bases divided by a median groove, or a sub- 
triangular pit, and is supported by a median septum extending for about one- 
half the length of the valve. The spirals have their apices directed laterally 
and consist of nine or ten volutions of the ribbon. External surface smooth. 
Shell-structure fibrous, impunctate. 
The external expression of the shells of Hindella is rendered peculiar by 
the fulness and close incurvation of the beaks, and these are distinscuishino; 
features. While the character of the loop is unique, the deep muscular scar 
of the pedicle-valve, the structure of the hinge-plate, and the smooth external 
surface, are features which demonstrate the close relationship of the genus to 
Meristina and Whitfieldella. 
Genus MERISTINA, Hall. 1867. 
PLATE XLVII. 
1828. Atrypa, Dalman. Kongl. Vetenskaps Akad. Handling., 134, pi. v, fig. 3. 
1860. Athyris, Roemer. Die Siluvische Fauna der westlichen Tennessee, p. 70, pi. v, fig. 12. 
1863. Mfrristella, Hall. Ti'ansactions of the Albany Institute, vol. iv, p. 212. 
1866. Meristella, Davidson. British Silui-ian Brachiopoda, p. 109, pi. xi, figs. 1-13. 
1867. Meristina, Hall. Twentieth Rejit. N. Y. State Cab. Nat. Hist., p. 157. 
1867. Meristina, Hall. Palaeontology of N. Y., vol. iv, p. 299. 
1872. Meristella, Hall and Whitfield. Twenty-fourth Rept. N. Y. State Cab. Nat. Hist., j). 196. 
1875. Menstina, Hall and Whitfield. Palaeontology of Ohio, vol. ii, p. 132, pi. vii, figs. 5, 6. 
1878. Meristella, Etheridge. Quarterly Journal Geological Society London, p. 597. 
^ All the internal characters of the valves hei’e described have been derived fi'om transverse sections of 
the shell. The material examined, most of which has been placed at our service by the kindness of its col¬ 
lector, Pi-ofessor Alpheds Hyatt, has afforded no interiors or single valves. The figures given above, of 
sections across the umbonal region, show some of the features mentioned. 
