Pvn H,i I'UitlS

51 PECTINID.E.
striae : colour red, pink, yellow, purple, brown, and rarely
milk-white, with streaks or blotches variously disposed :
margins rounded in front and at the sides, and notched or
indented by the ribs, sloping abruptly to the beak on each side
from a little above the middle ; upper side of the slope on the
right
hand of the lower valve toothed or serrate as in the
last species : beaks prominent : ears unequal and formed as in
P. pusio ; the right-hand one of the lower valve projects
beyond and slightly overlaps the opposite ear of the upper
valve ; their markings and the byssal notch are the same as in
the last species, as well as the cartilage, ligament, and internal
structure ; but the muscular scars are more distinct. L. 1*85.
B. 1-65.
Yar. 1. purpurea. Shell larger, broader, and natter : colour
purplish-brown marbled with yellow.
Yar. 2. nivea. Shell of the same shape as the last variety,
and having about 45 ribs : colour snow-white, sometimes tinged
with purple, or more rarely orange, yellowish, purple, or brown
of different shades. P. niveus, Macgillivray, Edinb. Xat. & Phil.
Journ. xiii. p. 166, pi. 3. f. 1 ; F. & H. ii. p. 276, pi. L. f. 2,
and (animal) pi. S. f. 3.
Habitat :
Equally common with the last species,, and
in similar situations; but it does not appear to have been
found on these coasts north of the Orkneys, whence
a white variety has been procured by the Rev. Dr. Smith
of Old Aberdeen. The range of depth varies from low-
water-mark at spring-tides to 40 fathoms. Yar. 1. Falmouth
harbour and off Portsmouth (J. G. J.) ; Cork
harbour (Humphreys); Bantry Bay (Barlee). Yar. 2.
Western coasts of Scotland, in 3-25 fathoms, on Lami-
naria saccharina and occasionally attached to stones ;
Glengariff, Bantry Bay (Barlee).
As a fossil or subfossil
this species is found, in the upper tertiaries of the Bel-
fast, Clyde, and Sussex beds. Abroad it is distributed
in every sea from Bergen (Sars) to theiEgean (Forbes);
and according to Weinkauff it is not uncommon on the
Algerian coast.