The description I gave in Malac. Groenl. p. 38 of the bathymetric occurrence ete. of the species
agrees exactly with the observations to hand; it was as follows: “It is already met with in 4—8 fm.,
most frequently in 15—20 im., but is nevertheless not rare in roo—120 fm. It has not been found in
greater depths than 120 fm. It is often found on muddy bottom, but is not rare on algal grounds,
stones or sand.”

Remarks. Smith states (Rep. Progr. Geol. Survey Canada 1878—79, p. 212 B), that his speci-
mens from Vancouver Island differ from the Atlantic specimens in several small respects; Holmes
(Occas. Papers Calif. Ac. Sc. VII, 1900, p.178) says that a specimen from Alaska agrees exactly with
specimens from the Atlantic, but that specimens taken between Alaska and Vancouver Island formed
a transition between specimens from the last-named island and from the Atlantic. Ohlin gives the
largest specimen as 95 mm., two specimens from Angmagsalik and Forsblad Fjord are 92 mm.; one
of the largest specimens from West Greenland is 85 mm.
