MIOCENE MOLLUSCA AND CRUSTACEA. 49 
Genus AXINASA Poli. 
AXINEA LENTIFORMIS?. 
Plate vu, figs. 5 and 6. 
Pectunculus lentiformis Conrad: Foss. Shells Tert. formations U. S., p. 36; Miocene 
Foss., p. 64, Pl. xxxvi, fig. 1; Tuomey & Holmes, Pliocene Foss. S. C., p. 48, 
Pl. Xvi, fig. 2; Emmons, Geol. N. Car., p. 286; Heilprin, Acad. Nat. Sei. Phil., 
1887, p. 402. 
Avinea lentiformis Conrad: Proc. Acad. Nat. Sci., Phil., 1862, p. 580; Meek, Check 
List, p. 5. 
Conrad gives a description of this species in his Fossils of the Median 
Tertiary, p. 64, as follows: ‘‘Lentiform, thick and ponderous, with fine, 
closely arranged, radiating lines, and distant more profound lines, giving the 
shell a slightly ribbed aspect; valves widest above or across the base of the 
umbones, where the margins are rather obtusely rounded; umbo large, and 
the summit prominent; dorsal margins oblique, curved; cardinal plate 
dilated, the teeth very large and oblique; marginal crenz rather narrow 
and approximate.” 
The specimens of Axinea which have come to me from the New Jersey 
beds are all small, young individuals; the largest being scarcely more 
than five-eighths of an inch in width—so small in fact that they scarcely 
show the true specific features, and I am somewhat in doubt as to which of 
these species to refer them, A. lentiformis, A. parilis, or A. passa. The 
shells are more circular in outline than any of the three except A. pavilis, 
while the teeth more nearly resemble those of A. lentiformis than of either 
of the others, being proportionally large and very distinct, while the inner 
extremities are very slightly inclined. In 4d. parilis and ii A. passa, the 
teeth are shorter than in the other, and are each more distinctly bent when 
the shells are fully grown; but in young specimens from Yorktown it is 
nearly impossible to distinguish the specifie features. The surface of the 
New Jersey specimens more closely resembles that of A. parilis than of 
any of the others, as the ribs are flat, with a simply impressed line dividing 
them, with about five longitudinal stria on each; while in the other species 
they are usually more rounded and prominent. Taking all these features 
MON XXIly——4 
