810 Report of THE STATE GEOLOGIST. 
slightly more than one entire volution. Toward the anterior 
margins of the primary lamellz a strong jugum is given off, its 
lateral branches projected very obliquely backward, sometimes 
scarcely rising between the coils, the union forming a broad angle 
\ 
XQ 
Fia. 386. Fia. 387. 
The brachidium of Protozyga exigua, Hall. 
on the anterior margin with a subacute process on the outer 
margin. 
(Type, Protozyga ewigua, Hall. Lower Silurian (Trenton 
limestone).) 
Hallina, N. H. Winchell and Schuchert. 1892. 
(Plate 40, figs. 6-8.) 
Shells small, oval in outline; valves biconvex and covered with 
numerous fine, sharp radial plications. Brachidium consisting of 
lateral processes making somewhat less than a single volution 
Fie. 388. Fia. 389. Fie. 890. 
Preparations showing the structure of the brachidium in Hallina Saffordi, Winchell and 
Schuchert. 
Fig. 388. The pedicle-valve cut so as to show the tips of the ascending lamelle. 
Fig. 389. The opposite side, showing the form of the primary lamelle as far as the base of 
the jugum, and the character of the latter. 
Fig. 890. View showing the brachidium in profile. 
and united by a simple, posteriorly directed jugum, situated near 
their anterior upward curvature. 
Type, Hallina Saffordi, N. H. Winchell and Schuchert. 
Distribution. Lower Silurian (Trenton limestone.) 
62 
