BRaAcHIOPODA. 769 
Hindella, Davidson. 1882. 
(Plate 32, figs. 18-20.) 
Shells subcircular or elongate-ovate in outline ; valves convex, 
the pedicle-valve being gibbous in the umbonal region. The 
hingeline is very short but the cardinal slopes are frequently 
long and transverse, which, with the fulness of the beaks of both 
valves, produce a “shouldered” appearance. There isa 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 deltidial plates and foramen. On the interior the teeth are 
moderately prominent and are supported by strong dental plates, 
Saas 
» Fies. 305,306. The primary lamelle and jugum of Hindella umbonata, Billings (sp.). 
which not only extend to the bottom of the valve, but are con- 
tinued 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 Meristiva and WuitrreLpeLa, with two diverg- 
ing crural bases divided by a median groove, or a subtriangular 
pit, and is supported by a median septum extending for about 
one-half thelength ofthe valve. Spirals everted; jugum situated 
anteriorly, very depressed, the lateral processes being directed 
backward in a low upward curve, uniting to form a short, straight 
undivided stem. [External surface smooth. Shell-structure 
fibrous, impunctate. 
Type, Hindella wmbonata, Billings (sp.). 
Two species are known, both from the Middle Silurian. 
97 21 
