MUTIELLA. Kil 



species is rare, and the opinions expressed by various authors appear to have Ijeeu 

 based entirely on the figures given by Sowerby. 



The hinge is similar to that of MutielUi coarctata (Zittel),' but shows some i)oints 

 of difference : thus the transverse corrugations or teeth on the expanded anterior 

 margin appear to be absent, and the terminal posterior lateral tooth cannot be 

 recognised with certainty. The points of resemblance, however, and the similarity 

 in the form of the shell and the character of the ornamentation seem suflicient 

 to justify the assignment of this species either to Mafielhi or to a closely 

 allied genus. 



From the figures given by Sowerby, Petiicola unc'ifortim appears to differ con- 

 siderably from P. cdiiallcnlata, but after an examination of the type of the former 

 I am led to the conclusion that it is not specifically distinct from the latter ; it 

 differs only in being more inequilateral, and the apparent difference in the uiiia- 

 mentation is due to the imperfect preservation of the surface of the shell in 

 1'. )iiicifoniiis. 



Tii[ics. — From Blackdown. The type of J'ctricukt caiudicniata cannot be found. 

 The type of P. nuclj'ormls is in the Bristol Museum. 



DistribHtioii. — Upper Greensand (zone of Scldamhacldd rostrala) of Blackdown, 

 and Peak llill, near Sidmouth. 



MuTiiiLLA larrrxMATA {(rOrhiijin/), 1 8^1-4. 



1844. Coums ROTVSBXTA, A. d'Oihi(jinj. i'ul. Fium;. Terr. Cix't., vol. iii, \> Ilo, 



pi. cclxxx, figs. 1— i. 

 1850. — — — Prodi-, de Pal., vol. ii, p. 1(32. 



18G7. — — E. Gtiiramjcr. Album Piilcout. do la Sarthe, p. 15, 



pi. six, figs. lU, 11. 



1870. — F. Itinner. Geol. v. Obersdiles., p. 3i0. 



1871. MuTiELLA KOTUNUATA, F. StoUczkci. Palujout. liidica, Cret Fauua S. ludia, 



vol. iii, pp. 247, 252. 

 1896. CoEBis KOTUNDATA, A. J. Jukes-Broione and W. Hill. Quart. Joiu-u. Geol. 



Soc.,vol. lii.p. 153. 



A portion of a right valve of MiUicUa rotuiulata from the Ccuomanian (Bed 11) 

 of Dunscombe, South Devon, was found and determined by the late C. J. A. 

 -Meyer. An internal cast was collected from Bed 10 of Beer Head by Mr. Jukes- 

 Browne, who also records the species from the Chloritic Marl of Maiden Bradley, 



' Fimbria coarctata, Zittel, ' Die Biv. d. Gosaugeb.,' pt. i (1864), p. 44, pi. vii, tig. 5. Kt-fonvd bv 

 Stoliczka, aud subsecjueutly by Zittel aud by G. Miiller, to the genus MutielUi. Compare also the 

 hiugeof Mutiella ruttindata figured by Guerauger, 'Album Pak'out. de la Sarthe' (1867), pi. xix, 

 fig. 11. 



