Pvn H,i I'UitlS

TAPES. 353
invariably the microscopical strise : colour yellowish-white,
often painted with two or three reddish-brown or purplish
rays of different widths, which are seldom entire, being generally
interrupted and divided into streaks, zigzag markings, or
spots of a most diversified kind ; the rays frequently appear
white, owing to the greater breadth of the darker bands ;
some specimens, as in T. aureus, are of a uniform pale yellow
or milk-white : epidermis horny, rubbed off in nearly every
part : margins obliquely but not much rounded in front, sharply
curved and produced on the anterior side, behind which the
line from the beaks is nearly straight, produced and wedgeshaped
on the posterior side, which is obliquely truncate and
ends in a blunt point, straight on the dorsal side in the young
but sloping gradually and with a slight curve in the adult :
beaks small, somewhat inflected, and close together ; umbonal
area not prominent : lunule lanceolate, longer than in T. aureus
but similar in other respects : corselet indistinct : ligament
rather long, yellowish-brown, wholly exposed, contained in a
marginal groove : hinge-line and hinge-plate as in the last species
: teeth, in the right valve three erect cardinals, of which
the posterior is the smallest, triangular, and set obliquely, the
middle cardinal is the largest and double or cloven ; the left
valve has the same number of cardinals, the smallest of which
is on the anterior side and set obliquely, and the other two are
double ; laterals indistinct : inside rather glossy, with a purplish
or orange tinge towards the beaks in bright-coloured specimens:
scars as in T. aureus. L. 1*6. B. 1*9.
Yar. 1. Sarniensis. Shell thicker, less produced at both
ends and consequently of an oval shape. V. Samiensis, Turt.
Dith. p. 153, tab. 10. f. 6.
Var. 2. elongata. Shell more produced and pointed at the
posterior end, being consequently more oblong
proportion to its length.
Habitat :
Every part of the British coasts,
and broader in
in sand
and among nullipore3, from the shore to 145 fathoms,
at which latter depth it was dredged by Capt. Beechey
off the Mnll of " "
Galloway. Garnsey was the first
recorded locality, as appears from Lister's '
Historia
Conchyliorum/ It occurs in all our upper tertiaries
from the Belfast deposit (Grainger) and glacial beds at