LAMELLIBRANCHIA TA. 
411 
CONOCARDIUM OHIOENSE. 
PLATE LXVIII, FIGS. 2, 3. 
Conocardium Ohioense, Meek. Pi-oc. Acad. Nat. Sci., Phila., p. 9. IS71. 
“ “ “ Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations : PI. 68, tigs. 2, 3. 
18S3. 
Shell small, ovate, sub-trigonal, ventricose behind the middle of its length; 
length one-third greater than the height. Posterior end prominent, pro¬ 
duced in the middle and sloping abruptly to the post-cardinal angle. Ante¬ 
rior end abruptly contracted in front of the middle and prolonged, nasute, 
with the extremity narrowly rounded. 
The body of the shell is marked by about six strong radiating plications 
on the ventricose portion of the valve, and on each side by more numerous 
and smaller plications. The interspaces between the ribs are marked by 
lamellose concentric striae. 
A specimen of this species has a length of 15 mm. and a height of 10 min. 
This species differs from C. cuneus in being more narrowly ventricose, and 
the body of the shell marked by fewer plications, with a distinct constriction 
in front; the nmbonal slope is more rounded and less oblique, while the poste¬ 
rior extremity is more produced than in the usual forms of C. cuneus and C. 
trigonale. 
Formation and localities. In the Corniferons limestone, near Columbus, Ohio, 
and at the falls of the Ohio river. 
CONOCARDIUM NORMALE. 
PLATE LXVIII, FIGS. 17-19. 
Conocardium normale, Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PL 68, figs. 17-19. 1883. 
Shell large, sub-ovate, trigonal; length about twice the height; basal margin 
regularly curving. Posterior extremity obliquely truncate. Cardinal line 
straight. Anterior end narrow, nasute. 
Valves ventricose, abruptly contracted anteriorly and truncate behind. 
Beaks posterior to the center, prominent, strongly incurved. Umbonal 
