and of a fine dark colour, with only a narrow
white band on the anterior basal edge. The edge is crenated, and the
muscular impressions are very distinct, and raised above the surface,
particularly that on the anterior valve, which is both pellucid and
tubercular.

18. Modiola (Tulipa ?) australis, Nob.
Modiola tulipa, var. 1. Lam. Hist. 6 pt. 1 111.

This Australian species will most probably prove to be distinct from the
American kind; but the specimen before me does not afford sufficient
materials to separate it, since there is only one water-worn valve in the
collection. It is not so distinctly rayed as M. tulipa, and the inside is
entirely of a brilliant pearly purple, except near the anterior basal
edge.

19. Lithophagus caudatus, nob.
Modiola caudigera, Lam. Hist. 6 pt. 1 116.
Icon. Ency. Meth. plate 221. f. 8. a, b.

20. Meleagrina albida, var. a. Lam. Hist. 6 pt. 1 152.

This appears to be a distinct species from those found in the Gulf of
Mexico and the West Indies, but the difference is not easy to describe.
The specimens before me, which are small, differ materially from some of
the same size among the American species. The outside is of a dull
greenish-purple colour, with a few distant membranaceous laminae which
are only slightly lobed, and not extended into long processes like those
of Avicula radiata (Zool. Misc. 1. t. 43.) which is the young of the
American kind. The internal pearly coat has a bright yellow tinge.

21. Spondylus radians ? Lam. Hist. 6 pt. 1 192.
Icon. Chemn. Conch. 7 t. 45. f. 469. 470. Ency. Meth. plate 191. f. 5.

22. Pecten maximus ? Lam. Hist. 6 pt. 1 163.
Ostrea maxima, Gmel. Syst. Nat. 1 3315.
Icon. Chemn. Conch. 7 t. 60. f. 585. Ency. Meth. plate 209. f. 1. a, b.

The shell before me is probably distinct from the above species, but is
too much worn down to be separated from it; in its present state it seems
to agree tolerably well with the species to which it has been referred.

23. Pecten asperrimus, Lam. Hist. 6 pt. 1 174.

This beautiful species was originally found by MM. Peron and Lesueur on
the coast of Van Diemen's Land.

24. Lima minuta (n.s.)

Testa ovato-oblonga valde tumida clausa radiatim costata, costis
transverse costato-striatis, auriculis minutis, margine crenato.

This shell, which was brought up by the deep sea sounding-lead, being
only one-sixth of an inch long, and one-fourth high, is the smallest
species of the genus. It is white, ovate, obl