186 CRETACEOUS LAMELLIBRANCHIA. 
since only imperfectly preserved specimens have been seen. The oblique striz, 
and the scales on the ribs, however, seem to connect it with P. Robinaldinus, but it 
appears to be distinguished by the regular alternation of large and small ribs, and 
by its greater size. LP. Stutchburianus presents some resemblance to one of the 
specimens from the Tourtia figured by d’Archiac! as P. acuminatus, Geinitz, but 
differs in the ribs being closer together and alternating in size. 
Remarks.—The examples from Haldon differ from the type in haying the seales 
on the ribs indistinct, but this difference is probably due to imperfect preservation. 
T'ype.—Blackdown Greensand ; in the Bristol Museum. 
Distribution Greensand of Haldon and Blackdown. 
Section Adquieecten, P. Fischer, 1886. 
(‘Manuel de Conch.,’ p. 944.) 
Proven (Aiquipecten) aspen, Lamarck, 1819. Plate XXXV, fig. 12; Plate 
XXXVI, figs. 1 a,b, 2, 3, 4. 
1770. M. Lister. Conch., pl. eccelxx, fig. 28. 
1813. Osrrea murticata, J. Townsend. The Character of Moses established for 
Veracity as a Historian, vol. 1, pl. i, 
fig. 2. 
1819. Prcren asper, Lamarck. Anim. sans Vert., vol. vi, p. 180. 
20. Prorrires asper, EF. 7. v. Schlotheim. Die Petrefactenkunde, p, 226. 
1822. Prcren asper, J. de C. Sowerby. Min. Conch., vol. iv, p. 95, pl. ceclxx, 
fig. 1. 
— — — A. Brongniart. Deser. géol. Envir. de Paris (in Cuvier’s 
Oss. Foss., vol. 11), pp. 320, 603, pl. v, 
fies Ie 
1825 — — Defrance. Dict. Sciences nat., vol. xxxviii, p. 261. 
1832. — — G. P. Deshayes. Encye. Mcth. Vers, vol. iii, p. 728. 
1883. —— — A. Goldfuss. Petref. Germ., vol. ii, p. 58, pl. xciv, fig. 1. 
1836 -- —  G. P. Deshayes and H. Milne Edwards. Ed. 2 of Lamarck’s 
Anim. sans Vert., vol. vii, p. 157. 
1837. — — F. Dujardin. Mém. Soc. géol. de France, ser. 2, vol. u, 
p. 228. 
— — — var. potontca, G., G. Pusch. Polens Palwont., p. 41, pl. v, 
fie. 7. 
1839. — — H. B. Geinitz, Char. d. Schicht. u. Petref. des siichs. 
Kreidegeb., pt. 1, p. 25. 
1 «Mém. Soe. géol. de France,’ ser. 2, vol. ii (1847), pl. xvi, fig. 3 (on the left-hand side, not the 
other fig. 3). 
2 T follow Dall in regarding AMyuipecten as only a section of Chlamys. Sve ‘Trans. Wagner 
Free Instit. Science of Philadelphia,’ vol. in (1898), p. 695. 
