CRENIPECTEN. 89 
Locality.—Two specimens from Lummaton are in my Collection. 
Remarks.—This pretty little species is distinguished by its wide and obliquely 
triangular form, its few and alternating ribs, and its central umbo. Of the accom- 
panying forms it most nearly approaches Pecten plicatus, Phillips, ‘ Pal. Foss.’ (not 
Sowerby), but that shell is distinguished by its much larger and coarser ribs (which 
seem all equal instead of alternating), by its greater breadth and its less obliquity. 
It differs from Pecten newxilis, Sowerby,’ by having much fewer ribs, and much 
smaller wings, and by being very much more oblique. Sowerby describes the 
ribs of his species as smooth, but in his figure these appear to be very fine close 
strie, which, however, are very much finer and closer than the threads in our 
specimens. 
Pecten Ottonis, Goldfuss,’ is very similar, but has much more numerous ribs 
and is less oblique. 
Pecten leonis, Semenow and Moller,* is less oblique and broader. Its ribs are 
more prominent on the umbo, and there seems little or no transverse ornament. 
P. plicatus, Sowerby,* differs widely from it both in shape and in ornament. 
2. CrenipecTten Ocean, Groldfuss, sp. Pl. X, fig. 6. 
1834-40. Prcormn Ocrant, Goldfuss. Petref. Germ., vol. ii, p. 41, pl. Ixxxviii, 
fig. 10. 
1841. —  putcatus, Phillips (not Sowerby). Pal. Foss., p. 137, pl. lx, 
fig. 80*. 
1848. — ILLEGALIS?, Bronn. Handbuch, pt. 3, p. 925. 
1848. — Ocrant, Bronn. Ibid., pt. 3, p. 928. 
1849. — = @ Orbigny. Prodrome, vol. i, p. 87. 
1853. —  puxicatus, Steininger. Geogn. Beschr. Eifel, p. 55. 
1854. AVICULOPECTEN PLIcATUS, Morris. Catal. Brit. Foss., p. 165. 
1888. — —- Etheridge. Foss. Brit., vol. i, Pal., p. 159. 
1889. AvicuLA PLICATELLA, Whidborne. Geol. Mag., dec. 3, vol. vi, p. 78. 
1891. AvicuLoPEctEN Ocrant, Frech. Abhandl. Geol. Specialk. Preuss., Band ix, 
pt. 3, p. 20, pl. xvii, fig. 10. 
Description.—Shell small, rather flat, nearly equilateral, slightly wider than 
long. Umbo low, flattened, acute. Hinge-margin unseen. Wings indistinct. 
Umbo defined by steep, lateral, straight declivities which end in the margin 
at about one-half the breadth of the shell. Lower part of anterior margin 
1 1840, Sowerby, ‘ Geol. Trans.,’ ser. 2, vol. v, pt. 3, pl. lii, figs. 1, 2. 
2 1834-40, Goldfuss, ‘ Petref. Germ.,’ vol. ii, p. 282, pl. clx, fig. 5. 
3 1863, Semenow and Moller, ‘ Mél. Phys. et Chim.,’ vol. i, p. 708, fig. iv, fig. c. 
4 1827, Sow., ‘Min. Conch.,’ vol. vi, p. 144, pl. dixxiv, fig. 3. 
VOL. Il. 12 
