136 PALEONTOLOGY OF NEW JERSEY. 
Order SCUTIBRANCHIATA. 
Family FISSURELLID 2. 
Genus FISSURELLA Lamarck. 
FISSURELLA GRISCOMI. 
Plate xxiv, figs. 11-14. 
Fissurella Griscomi, Conrad: Jour. Acad. Nat. Sci. Phila., lst ser., vol. 7, p. 143; 
Miocene Foss., p. 78, Pl. XLiv, fig. 8; Proc. Acad. Nat. Sci. Phila., 1862, p. 570; 
Meek, Check List Miocene Foss., p. 14; Heilprin, Proc. Acad. Nat. Sci. Phila., 
1887, pp. 397, 399, and 404; Tert. Geol. U.S., p. 8. 
“Shell ovate-oval, compressed, rather elevated, cancellated; radiating 
ribs crowded, somewhat alternate in size; fissure long, inclined, nearest to 
the anterior end; within somewhat thickened on the margin, which is eren- 
ulated; an impressed submarginal line.” (Conrad: Jour. Acad. Nat. Sei., 
vol. 7, p. 143.) 
‘“‘Subovate, elevated, laterally compressed, with alternating radiating 
robust striee, and strong prominent transverse lines; foramen narrow, sub- 
ovate; inner margin crenulated.” (Conrad in Miocene Fossils.) 
This species is among the most abundant forms in the New Jersey 
Miocene marls, and attains a very fair size, one individual before me meas- 
uring almost 14 inches in length, nearly 1 inch in its greatest width across 
the base, and seven-eighths of an inch in height. The form is elongate- 
ovate on the margin, widest below the center; surface highly conical, mod- 
erately convex on the long side of the apex and very gently concave on 
the short side; apex broadly perforated in the older shells, the perforation 
often keyhole-shaped in half grown specimens, but more often elliptical, 
and usually bordered by a flattened callus internally. Surface with very 
numerous raised radiating lines, more or less alternating in size and rounded; 
these are crossed by strong concentric lines of growth and firm ornamental 
lines which crenulate the radii. Inner margin strongly crenulated. 
Among the numerous specimens present in the collections there is no 
one feature of the shell that does not show considerable variation. In some 
the striz are strongly alternating in size; on others they are very even. 
On two different individuals of about the same dimensions, in the space 
