66 
BULLETIN OF THE LABORATORIES 
Genus Prothyris, Meek. 
Frothy ris m,eeki, Wmchell. 
This species occurs frequently in the shale below congl. II, but 
is by no means limited to that horizon. Its range and legitimate lim- 
its of variation have not been fully studied. 
San^uinolites {Goniophora) senilis, sp- n. 
(Plate IX, Fig. 28.) 
Cf. Sanguinolites cuneatus, DeKoninck, and Goniophora siibrecta. 
Hall. 
Shell of rather large size, nearly rectangular, hinge and ventral 
margins nearly parallel, nearly straight and of nearly equal length. 
The anterior dorsal margin is nearly straight, making with the hinge 
an angle of about 120° or less, somewhat produced; posterior margin 
truncate at about a right angle and again obliquely truncate at the up- 
per third (sometimes apparently curved rather than doubly truncate ; 
'in most specimens the postero inferior angle is more acute and pro- 
duced than in the one figured, thus approaching G. subrecta, H.) 
Surface quite convex along the very prominent and rather acute post- 
umbonal ridge, the greatest convexity being half way from the beak 
to the postero-ventral angle; On either side of the ridge the surface 
is plane for some distance, but anteriorly becomes conca ve, forming a 
broad sulcus passing from the middle of the ventral margin toward the 
beak; posteriorly the surface is flat for a considerable distance from 
the upper angle. The umbo is rather prominent. The surface is or- 
namented with very prominent, rather irregular, close, concentric 
lines, which are acutely angled upon the umbonal ridge. Length 60 
mm; height 25 mm; beak distant from the anterior about ii mm. 
Found only in shales four feet below conglomerate I, near Granville, 
O. In some specimens the resemblance to S. cuneatus, Dekon., ap- 
proaches identity. From Goniophora subrecta it differs chiefly in the 
less elevated anterior extremity and slightly less produced infero-pos- 
terior angle. The relation is so obvious that we regard this shell as 
increasing the Devonian character of our division I. 
