78 
BULLETIN OF THE LABORATORIES 
truncate above ; finally, we are not sure the hinge structure is that of 
Edmondia. 
To all appearance our specimens agree with the smaller form fig- 
ured in Vol. V, Pal. N. Y. , Part I, under the name Macrodon ovatus, 
though its relation to the typical larger form is less obvious. In some 
of our specimens the teeth of Macrodon were doubtfully observed. 
Ctenodofita {.Kucida) iowensis, w. and w. 
(Plate I, Figs. 14, 17.) 
A nuculoid shell resembling the one quoted is very common in 
the layer below congl. I. 
Shell small, triangularly subovate, quite ventricose. Beaks about 
one-fourth or less from the anterior, prominent, acute, and incurved. 
Hinge abruptly bent at a little less than a right angle with about 10 
posterior and 4-5 anterior teeth, anterior margin obliquely truncate; 
lower margin a nearly regular semi-elliptical curve. Surface marked 
by numerous plicae, especially near the margin, where the epidermis 
is thickened. Length 10.5 mm, height 8 mm, thickness 6 mm. (?) 
Ctenodonta {Kiicula) stella, Win. 
(Plate IX, Fig. 14.) 
“Shell very small, elliptic-ovate, with sub-central beaks. Ante- 
rior cardinal slope arched, posterior nearly straight ; extremities rather 
sharply rounded ; ventral side semi-elliptic. Anterior hinge-plate with 
17 minute, acute teeth; posterior with five. Beaks a little attenuated 
near the extremity, curved inwards and backwards. Shell thin, with 
delicate concentric striae.” 
This species occurs with C. iowensis, in shales below congl. I. 
Ctenodonta {Kncula) how^htoni, Stevens? 
(Plate V, Fig. 17.) 
A small species collected by Mr. Deming, in the shales over congl. 
II. is very like N. ventricosa, H. 
Shell small, transversely sub-oval; height equal to ^ the length; 
