218 THE ESSEX NATURALIST.
A similar shell is described by M. M. Bucquoy, Dautzenberg
and Dollfus (Moll. Mar. du Roussillon, v. ii., p. 23, pl. V., fig. 7, 8,
9), as O. stentina var. pepratxil, and an odd valve from Tripolitana
is described by Monterosato. The British shell is rather variable,
and may be the same, but I have no means of comparing the
two.
OSTREA ROSTRALIS (in Reeve).
Reeve (op. cit., pl. x.,fig. 20), describes this shell as oblong,
rugged, upper valve lamellate, the other excavated and longi-
tudinally grooved, beak prominent, Hab. Mediterranean. The
British Museum specimens and my own are from Portugal (Tagus
region).
This shell is elongated and irregular, undulated, striped
and variegated brown and purple on a whitish ground. Beak
acuminate, narrow arid produced, under valve overlapping the
upper one. The apex is normal and not undercut as in O. angulata ;
interior usually a chalky white, exterior of lower valve
smooth, and ivory white in colour. The York Museum has a
very fine upper valve of this type (plate xviii., fig. 28), obtained
by myself from the Lusitanian deposit at Selsey in Sussex, but as
the figure shows, it is rather more ovate than the usual run of
Portuguese examples, and may represent another or allied species.
Sir Gardner Wilkinson, in a note on Ostrea virginica (Zoologist,
1865, vol xxiii, p. 9558,), says he found that shell at Tenby, where
he was residing, naming it specifically the Ostrea virginica of
Spain, he having collected it at Cadiz. His largest Tenby speci-
men was 51/2 inches long, 33/4 inches at its widest part, and 13/4
inches deep. He remarks further that the beak, and with it
the hinge, in a full grown Spanish shell frequently become
depressed or bent downwards. This feature does not appear
in the Selsey shell. It can hardly be termed a specific character
as the same aberration of the apex appears in others of the long
oyster type (p. 191).
I have obtained from the Thatcher Rock and Hope's Nose,
Torbay, a number of specimens that appear to correspond with
Wilkinson's shell; the one figured (pl. xviii., fig. 27) from the
the Thatcher is thick, flat, with a length of 105 mm. and
breadth of 65 mm.