Pvn H,i I'UitlS

316 CYPRINIDJE.
a bevelled edge :
pallial
and muscular scars as in the last
species, but the latter are more deep. L. 0-5. B. 0*5.
Tar. 1. globosa. Shell much larger, and usually more con-
vex, inclining to a circular shape, with flue and regular ribs,
which in the adult generally disappear towards the front and
sides. L. 0-8. B. 0*9. A. globosa, Moller, Ind. Moll. Groenl.
p. 20.
Yar. 2. striata. Shell more closely ribbed. A. striata
(Nkania striata, Leach),
Moll. 1. c.
Yar. 3. nana. Shell much smaller, either smooth or partly
ribbed. L. 0-225. B. 0-225.
Habitat :
Sand, often mixed with mud,
in 20-50
fathoms, off Scarborough (Bean), and Mull (Bedford) :
the typical form appears to be very local. Subfossil in
25 fathoms off Larne, co. Antrim. Var. 1. Rather
common off Skye, the coasts of Argyle and Ross, and
east of Shetland, in 30-80 fathoms. It resembles in
shape Corbicula (or Cyrena) fluminalis. Y r ar. 2. Plen-
tiful on the coasts of Yorkshire, Northumberland, and
Durham, Firth of Forth, west of Scotland, and outer
at from 3 to 50 fathoms.
Hebrides, in sand and mud,
This variety occurs in all our newer tertiaries, as far
back as the Red Crag ; and it is peculiar to the glacial
deposits. Var. 3. Fifteen miles N.W. of Mull (Bed-
ford) . It seems to present a link connecting the pre-
sent with the next species. A. compressa, and parti-
cularly the variety striata, are extensively distributed
throughout the North Atlantic from Spitzbergen and
the White Sea to the Cattegat, as well as on the north-
eastern coasts of America, at depths varying
from 10 to
140 fathoms. It is found in the Uddevalla and other
similar deposits in Scandinavia; Risso has recorded it,
under the name of Cyprina Montagui, as fossil in the
tc
terrains diluviens " at Nice ; and Drexler found it in
pliostene " strata in Hudson's Bay.