LAMELLIBRANCHIA TA. 
503 
Test thin, marked by fine, regular concentric striae, which become crowded 
on the anterior end and sometimes fasciculate on the body of the shell. 
Interior unknown. 
A medium-sized specimen has a length of 14 mm. and height of 8 mm. 
A larger specimen measures 15 mm. in length and 9 mm. in height. 
This species is distinguished by its small size, regularly curving base, and 
symmetrical posterior extremity. 
Formation and localities. In the soft shales of the Hamilton group, on the 
shores of Seneca and Cayuga lakes. 
Elymella nuculoides, n. sp. 
PLATE XL, FIGS. 6, 7, S, 10? 
In part Modiomorpha? hyalea, Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PL 40, fig-s. 
5-11. 1S83. 
Not “ “ “ Prelim. Notice Lamellibranchiata, 2, p. 79. 1870. 
Shell small, broad, obliquely ovate; length more than one-half greater than 
the height; basal margin regularly curving, more abruptly recurving at the 
anterior end ; posterior margin regularly rounded, recurving into the cardi¬ 
nal line, which is straight for half its length. Anterior end short, regularly 
rounded. 
Valves moderately convex on the posterior and ventral portions, becoming 
gibbous in the middle and umbonal regions. 
Hinge-line straight, extending a little less than half the length of the shell. 
Beaks anterior, prominent and incurved, rising little above the hinge-line. 
Umbonal region regularly gibbous, without defined ridge. When the shell 
is partially compressed, it develops an undefined ridge in the line of the 
umbonal slope. 
Test moderately thick, marked by fine concentric stride which are fascicu¬ 
late on the body of the shell, giving rise to strong undulations. Interior 
unknown. 
A medium-sized specimen has a length of 28 mm. and a height of 17 mm. 
A larger individual measures 30 mm. in length and 18 mm. in height. 
