36 
BULLETIN OF THE LABORATORIES 
Chonetes scitula. Hall. 
(Plate I, Fig. 4. ) No. 1397. 
Shell small, semi-oval, hinge-line about equal to greatest width, 
tumid along the medial line. Ventral valve, moderately convex along 
a line from the beak to the front margin, about one-third the entire 
width, thus elevated near the front, lateral margins depressed; beak 
slightly prominent, hinge-line somewhat angled, armed at either ex- 
tremity with at least two spines. Surface marked by fine but rather 
prominent, distant striae which do not bifurcate, sometimes somewhat 
alternate. Width about 8 mm, height 5 mm. Dorsal valve nearly 
plane. Near the base of the series at Moot’s run, probably 50-60 feet 
below congl. I. 
Our specimens agree even to details of hinge structure with 
those of New York. The spines are strong and oblique. 
Another form found near congl. II, or about 80 feet above the 
present species, resembles this in form, but has more numerous bifur- 
cating striae. This we compared with C. setigera, H., but though 
closely agreeing otherwise, our species has oblique spines on the hinge. 
Chonetes tumidiis, sp. n. 
(Plate II, Fig. 21.) 
Shell of medium size, closely resembling C. acutiradiata of the 
Corniferous group of New York. 
Ventral valve very convex (as much so as C. hemispherica of the 
Upper Helderberg), hinge extended, with mucronate extremities, 
straight, apparently with few oblique spines; body of the shell nearly 
semi-circular, forming nearly a segment of a sphere, being suddenly 
depressed to the flat ears, which are acutely triangular. Umbo some- 
what prominent. Surface marked by numerous (50), regular, nearly 
continuous, rounded striae, which rarely bifurcate. Exfoliated speci- 
mens show numerous oval pores between the striae. Dorsal valve not 
known. This very pretty species is found in the irregular calcareous 
nodules at base of the section at Moot’s run and adds a significant 
Devonian color to the facies. The resemblance to C. hemispherica is 
close, but the outline is as in C. acutiradiata, H. 
Width 12 mm, height 7 mm. 
