Pvn H,i I'UitlS

ARCA. 173
mens obtained by Sars and MfAndrew on the coast of
Finmark at depths of from 20 to 160 fathoms are smaller
than the Greenland shells; bnt those from our own
seas and more southern latitudes dwindle into insigni-
ficant proportions compared with any of the above.
M fAndrew has also dredged this species alive off Gib-
raltar, in 45 fathoms, and Forbes in the iEgean, in
200 fathoms. Two specimens which I procured from
water off the north coast of Shetland were at-
deep
tached bv the bvssus to tubes of Pomatoceros arietinus,
and I kept one of
Muller [Ditrupa subulata, Berkeley) ;
them alive for more than a day. Soon after it was put
into a glass vessel and had a fresh supply of water,
it left
its plug of attachment on the Annelid case, and crawled
away at a fair pace on its narrow foot, the valves of its
shell spread out with the beaks uppermost. The action
appeared
to be similar to that of Galeomma Turtoni.
The shell has all the characteristics of Lamarck's
genus Cucullcsa, the side teeth being nearly parallel
with the hinge-line, and consequently at almost a right
angle
angle
to the central teeth or crenulations. But this
varies in different individuals and at successive
of the side teeth is
periods of growth, and the position
more frequently oblique than horizontal. The central
teeth are often wanting. I therefore abstain from
removing this species from Area,
as well as from offer-
ing any opinion as to the value of Lamarck's genus.
Mr. G. B. Sowerby was the first to notice the inequality
of the valves in Cucullcea.
Dr. Torell called my attention to the probability that
the present species might be identical with the A.
glacialis of Gray. Professor Sars had previously ex-
and in his Report on the so-
pressed the same opinion ;
called glacial formation in the Diocese of Christiania.