LAMELLIBRANCHIA TA. 
347 
Pal^eoneilo truncata. 
PLATE L, FIGS. 40, 41. 
Palceoneilo truncata, Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PL 50, figs. 40, 41. 1883. 
Shell of medium size, trapezoidal; length about twice the height; basal 
margin nearly straight or slightly concave in the middle; posterior margin 
retrally truncate, acutely rounded above into the cardinal line, which is very 
slightly arcuate. Anterior end rounded. 
Valves convex below, becoming gibbous in the middle and upper part. 
Beaks at about the anterior fourth, somewhat prominent, rising above the 
hinge-line. Umbonal ridge broad, distinct. Post-cardinal slope depressed, 
marked above by an undefined elevation near the hinge-line. 
Test thick, marked by fine, closely-arranged, concentric striae, which in 
some parts are crowded and fasciculate, but which do not rise into regular 
lamellar expansions. Interior unknown. 
The two specimens described measure respectively 30 and 24 mm. in 
length, and 15 and 12 mm. in height. 
This species may be compared with P. muta, but it is a proportionally longer 
shell, the basal and cardinal margins are nearly parallel, the beaks are more 
anterior, and the shell surface is not raised in regular lamellar expansions. 
Formation and localities. In the sandstones of the Waverly group, at Rich¬ 
field and Medina, 0. 
PALiEONEILO SULCATINA. 
PLATE L, FIGS. 42-46. 
Nuculites sulcatina, Conrad. Jour. Acad. Nat. Sci., Phila., vol. viii, p. 250, pi. 15, fig. 10. 1842. 
Leda nuculiformis, Stevens. Am. Jour. Sci., series 2, vol. xxv, p. 262. L858. 
“ Barrisi, White and Whitfield. Proc. Boston Soc. Nat. Hist., vol. viii, p. 29S. 1862. 
Palceoneilo Bari'isi (White and Whitfield), Hall. Prelim. Notice Lamellibrancliiata, 2, p. 11. 1870. 
“ “ “ “ “ Pal. N. Y., vol. v, pt. 1. Plates and Explanations: 
PI. 50, figs. 42-46. 1883. 
Nucula Hubbardi, Winchell. Proc. Acad. Nat. Sci., Phila. 1862. 
Shell of medium size or larger, sub-elliptical or narrowly ovate; length nearly 
twice the height; basal margin regularly curving. Posterior extremity 
narrowly rounded, with sometimes an obscure retral truncation. Cardinal 
line gently arcuate. Anterior end regularly rounded. 
