OF DENISON UNIVERSITY. 
93 
anteriorly, becoming less distinct posteriorly. A portion of the shell 
where preserved shows the ridges far less defined than on the cast. 
Length, 37 mm.; height, 25 mm.; convexity, 25 mm. 
Locality and position. Soldiers’ Home, Clinton Group. Collection 
of Mr. Geo. Caswell. 
GENUS CYPRICARDITES, Conrad. 
III. Cypricardites ferrugineum. Hall and Whitfield. 
Species described in Ohio Pal. Vol. II. 
Locality a 7 id position. , Wilmington, Clinton County, Ohio, Clinton 
Group. To my knowledge not found elsewhere. 
GENUS NUCULA, Lamarck. 
IV. Nucula minima, sp. n. 
{Plate XLV, Pigs. 8 a, b, c.) 
Shell (presumably the cast) very small, ovoid, gibbous above the 
middle towards the beaks, outline curving to the base and posterior 
extremity, anteriorly curving more rapidly to the beaks above. Beaks, 
near the anterior extremity of the shell, incurved and inclined for- 
wards. Hinge line at one-third the distance from the beak to its pos- 
terior extremity supplied on each side with a narrow fold, directed 
backwards, making a small angle with the hinge line, and vanishing at 
one-third the distance from the posterior extremity in the depressed re- 
gions formed by the raised postero-umbonal regions. 
Near the beak on each valve are three to four radiating grooves, 
which are characteristic of this species and are evident under the mi- 
croscope. 
In addition to these grooves are three more or less clearly defined 
pits, one being placed in the anterior groove near the beak, and the 
two others in the second groove, one on each side, and at a greater 
distance from the beak. Along the hinge line, anterior to the beaks, 
are two or three more or less distinct crenulations, which appear a little 
like plications originating in the lunule near the beak and becoming 
more distinct at the hinge line. 
Length, 2 mm.; height, 1.4 mm.; convexity, i mm. 
Locality and position. Beavertown marl, Huffman’s Quarry; not 
found elsewhere in the Clinton Group. Associated with many other 
