Fam. 2 , Plate 4.
TRITONIA LINEATA, A l d e r a n d H a n c o c k .
T. gracilis, alba, pellucida; dorso linesi alba opaci utrinque notato; velo processibus linearibus 4;
brancbiis parvis, pinnatis, utroque dorsi latere 5.
Tritonia lineata, Aid. and Hanc., in Ann. Nat. Hist., 2d ser., v. 1, p. 191.
Hab. Under stones between tide-marks, Scarborough, J. A.
Body five eighths of an inch long, very slender, linear, pellucid white, with an opaque
white line along each side of the back; sides parallel. Veil rather narrow, produced in front
into four long filaments, the two nearest the centre longest. They are pellucid, with opaque
tips. Tentacles entire and colourless below, pale yellow above, and divided into several stems,
with delicate and slender laminae or branches. The principal stem, situated posteriorly, is.
thicker and longer than the rest, and truncated at the top. Sheaths rather long and tightish,
expanding a little above; the margins undulating. The eyes are distinctly seen behind the
tentacles. The back is very delicately, scarcely perceptibly, tuberculated, and from its
transparency shows the viscera through of a pale yellowish or rosy hue. The two opaque
white lines unite into a point above the head in front, diverging thence toward the tentacles,
and are continued along the sides of the 'back, curving outwards opposite each pair of
branchial tufts; they unite again posteriorly, and are continued in a central line to the tail.
The pallia! ridge is somewhat produced. Branchiae rather slender, imperfectly bipinnate,
transparent, white, with an opaque white line in the centre of each, running into those on
the back: there are four or five pairs of branchial tufts, the posterior ones very small. Head
scarcely distinct from the veil, the mouth opening inferiorly. Foot slender, rounded in front,
and tapering to a point behind; the liver forming a reddish-yellow patch down the centre.
We obtained this delicate and graceful little Tritonia,—very distinct from anything
before recorded,—under large flat stones among the rocks north of Scarborough, which we
explored in September, 1846, in company with our friend Mr. Bean. Two specimens only
were found, one by ourselves, and a second by that gentleman. They lived with us for some
time, and deposited one or two patches of spawn. The eggs are imbedded in a narrow,
transparent belt, rather closely coiled about four times.
Figs. 1, 2, 3. Tritonia lineata, different views.
4. A tentacle, more highly magnified
5. A branchial tuft.
6. Spawn (the coil is reversed by mistake).
7. A small portion of the same, showing the eggs.