862 Report oF THE State GEOLOGIST. 
valve, and the recurvature of the ascending branches exceedingly 
slight. This recurved lamella is so delicate that it is rarely com- 
pletely preserved, but when retained, the entire brachidium has 
Fa. 496. Fia. 497. 
Fie. 496. Eunella simulator, Hall; showing the character of the hinge-plate, the relative length 
and usual preservation of the brachidium, with the ascending band lost. 
Fia. 497. Hunella Sullivanti, Hall; a dorsal view of the complete brachidium. 
the form represented in the adjoining figure. The crural 
apophyses are situated more anteriorly than in CryprronELia and 
are much broader at the base. 
Type, Hunella Sulliwanti, Hall (sp.). Devonian. 
Harttina, Hall. 1893. 
(Plate 52, figs. 29-31.) 
Shells plano-convex or naviculoid ; brachial valve depressed- 
convex or nearly flat and the pedicle-valve medially ridged with 
abrupt slopes at the sides. Dental lamelle of the pedicle-valve 
well developed. In the brachial valve there is a short, tripartite 
hinge-plate, supported by a median septum of considerable height 
in the umbonal region and extending for fully one-half the length 
of the valve, becoming low anteriorly. 
The crura are very short and are continued almost immediately 
into the long convergent crural apophyses. The descending 
branches of the brachidium extend for nearly the entire length 
of the shell, following the curvature of the valve and approach- 
ing each other anteriorly, their extremities being again directed 
outward. The ascending branches extend backward to points 
not far in front of the crural apophyses, where they are united 
by a transverse band. The outer margins of the descending 
114 
