LAMELLIBRANCHIA TA. 
409 
CONOC ARDIUM, Bronx. 1835. 
CoNOGARDIUM CUNEUS. 
PLATE LXVII, FIGS 1-32; PLATE LXVIII, FIGS. 1,4-16; AND PLATE XCIV, FIGS. U, 12. 
Pteurorhyuchus cuneus, Conrad. Geol. Surv. N. Y., Ann. Rep., p. 206. 1840. 
Conoeardium cuneus (Conrad), S. A. Miller. Cat. Am. Pal. Foss., p. 187. 1877. 
“ “ “ Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations : PI. 67, figs. 21- 
27, 29-32. 18S3. 
Pleurorliynclms attznuatus, Conrad. Jour. Acad. Nat. Sci., Phila., vol. viii, p. 253. 1842. 
Conoeardium attenuatum (Conrad), S. A. Miller. Cat. Am. Pal. Foss., p. 187. 1877. 
“ “ ? “ Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 67, figs. 
1-11. 1883. 
PleurorliyncTius trigonalis, Hall. Geol. Surv. N. Y., Rep. Fourth Dist., p. 171, t. 67, figs. 6, 6a. 1843. 
Conoeardium trigonale (Hall), S. A. Miller. Cat. Am. Pal. Foss., p. 187. 1877. 
“ “ “ Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 67, fig. 28; pi. 68, 
figs. (1 ?), 4-16. 1883. 
Conoeardium nasutum, Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI 67, figs. 12-20. 1883. 
Bilobites, De Kay.* Ann. Ly. Nat. Hist. N. Y., vol. i, p. 45, pi. 5, figs. 1-4. 1824. 
Shell large, angularly sub-ovate, or trigonal in outline; length less than twice 
the height; basal margin gently curving from the post-inferior extremity to 
the anterior end. Posterior extremity abruptly truncate, produced into a 
tubular extension along the cardinal line. Cardinal line straight, margins 
inflected toward the anterior end. Anterior end more or less rapidly atten¬ 
uate, with the margins gaping before reaching the extremity. 
Valves gibbous. 
Beaks sub-central, vertical, prominent and closely incurved over the binge¬ 
line. Umbonal slope angular, usually strongly defined, extending to the post¬ 
inferior extremity. Post-cardinal slope flat or concave. 
Test thick, composed of two distinct layers. Surface marked by numer¬ 
ous radiating plications and intermediate arching lamellose, concentric striae 
on the body of the shell. The posterior slope is ornamented by curving 
radii, extending from the beak to the posterior margin, with the interspaces 
marked by transverse lamellose striae. From the entire periphery of the 
umbonal ridge there extends a finely striated expansion of the shell, which 
increases in extent from the beaks downward, and in old shells is supported 
anteriorly by a thickening of the shell along the basal margins, which often 
* Note on the Organic Remains termed Bilobites, from the Catskill Mountains. By J. E, Da Kay, M. D. 
Read October 13, 1823, 
