158 SUPPLEMENT TO THE CRAG MOLLUSCA. 
fragmentary) in the Middle Glacial at Hopton, and in all these deposits it is the thin and 
non-rugose form that occurs. At Bridlington I believe it is not uncommon, but there 
and at Dimlington it is the gigantic rugose form that occurs. 
Saxtcava? rraciuis, Vyst. Crag Moll., vol. ii, p. 288, Tab. XXIX, fig. 6. 
Localities. Cor. Crag, Sutton, and near Orford. 
This shell was described by Montague under the name Mytilus plicatus ; but plicatus 
of Chemnitz is a different species inhabiting the Nicobar Islands. I have, therefore, 
retained Nyst’s name for our shell. 
There are two or three small bivalves which have been hitherto called by different 
generic names, and have as yet no proper resting-place, and which I consider ought to 
have a distinctive generic appellation of their own. The first of these is the above 
Jraglis. Another is Sawicava ? carinata (‘ Crag Moll.,’ vol. ii, p. 289, Tab. XXIX, fig. 
5), which I believe to be specifically distinct from /ragilis ; while it seems probable that a 
fossil of the older tertiaries of America called by Lea (‘ Contrib. to Geol.,’ p. 48, pl. i, 
fig. 16) Byssomia petricoloides may prove a third; but the hinge of Lea’s specimen is 
not perfect. 
The subjoined list of synonyms shows how the first of these shells, /ragi/is, has been 
bandied about from genus to genus : 
Mytilus plicatus, Mont. Test. Brit. Suppl., p. 70, 1808. 
Saxicava plicata, Turt. Brit. Biv., p. 22, 1822. 
— ? fragilis, Nyst. Coq. Foss. de Belg., p. 97, Pl. 4, fig. 10 a, 6, 1843. 
— rugosa juv., Forb. and Hanl. Brit. Moll., vol. i, pl. 6, figs. 1—3. 
Sphenia cylindrica, 8. Wood. Catalogue, 1840. 
Magdala plicata, Gray. Last of Brit. Biv., p. 161, 1851. 
Anatina — id. Ann. of Philos., 1825. 
Psammobia?— _ Jeffreys. Ann. and Mag. Nat. Hist., vol. xix, p. 314. 
Lyonsia — Forb. and Hanl. Brit. Moll., vol. 1, p. 218, 1853. 
Panopea — Jeffreys. Brit. Conch., vol. i, p. 75, 1865. 
Myrina oceanica, Conti., 1864. Hide Jeffreys, Brit. Conch., vol. v, p. 192. 
SPHENIA OvaTA? Crag Moll., vol. ii, p. 276, Tab. XXIX, fig. 7 (as S. Binghami). 
Locality. Cor. Crag, Sutton. 
The shell figured in the ‘Crag Mollusca’ was referred with doubt to the recent 
British species Bingham. Dr. P. Carpenter, however (‘ Geol. Mag.,’ vol. ti, p. 153), says 
that the Crag shell more resembles Sp. ovata from the north-west coast of America. 
