464 
PALAEONTOLOGY OF NEW YORK. 
TELLINOPSIS, Hall. 4870. 
Tellinopsis subemarginata.* 
PLATE LXXVI, FIGS. 21-31. 
Nuculites subemarginata, Conrad. Jour. Acad. Nat. Sci., Phila., vol. viii, p. 249, pi. 15, fig-. 5. 1842. 
Tellinopsis subemarginata (Conrad), Hall. Prelim. Notice Lamellibranchiata, 2, p. 80. 1870. 
“ “ “ “ Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 70, 
fig-s. 21-31. 1883. 
Shell large, elliptical, sub-quadrate; length more than once and a half the 
height. Basal margin straight or gently curving. Posterior extremity sub- 
emarginate in the middle and rounded above and below, sometimes truncate 
or rounded with no emargination. Cardinal line gently arcuate. Anterior 
end regularly rounded, large, usually equaling or greater than the posterior 
half of the shell. 
Yalves moderately convex below and toward the extremities, becoming 
gibbous in the middle and umbonal region. 
Beaks sub-central, rather prominent, elevated above the hinge-line and 
incurved. Umbonal slope rounded, distinct, defined above by a depression 
which is sometimes a furrow extending from the beak to the middle of the 
posterior margin or below, producing a slight emargination. The post-cardi¬ 
nal slope above the depression is convex. 
Surface marked by fine concentric striae, which are sometimes fascicled, 
producing undulations of the surface, and also by radiating striae which are 
more or less distinct. From the anterior side of the umbo there extends a 
battened space, limited on each side by a low ridge, extending to the antero- 
basal margin, producing an undulation in the direction of concentric striae. 
Five specimens measure respectively 20, 26, 28, 31 and 49 mm. in length, 
and 12, 16, 16, 19 and 28 mm. in height. 
This species has apparently no relation with any other form described in this 
* A well-marked specimen of this species in the-author’s collection bears the following label in Mi-. Con¬ 
rad’s handwriting: “ Posidonia tellinoides, Conrad. Outline fig., p. 1.” The reference is to a plate of outline 
figures never published, and the writer has not found the name recorded in any publication of Mr. Conrad. 
