EOLIS OLEVACEA.
EOLIS OLIVACEA, Alder and Hancock.
E. flarido-alba, maculis albis; branchiis paucis, crassiusculis, cylindraceis, olivaceis, senebus 6-8
digestis; tentaculis limbus; angulis anterioribus peifis breribus, obtusis.
Eolis olwacea, Aid. and H u e . in Ann. Nat. Hist. v. 9, p. 35. B I
Hat. Under stones between tide-marks, Whitley and Cullercoats, Northumberland, not uncommon.
Whitburn, Durham. Rothesay Bay, Isle of Bute.
Body about half an inch long, pale yellow or yellowish white, sprinkled with minute spots
of opake white. Dorsal tentacles rather short, nearly linear, ohtuse, approximating at the
base, yellow speckled with white, and having a more or less distinct orange-red hand m the
centre. Oral tentacles not so long as the dorsal ones, linear and obtuse, arismg from the
upper surface of the lips. A streak of orange or rose-red extends on each side of the head
between the oral and dorsal tentacles, curving inwards, and is continued behind the latter a
short way down the hack; in some brilliantly coloured varieties there is a large sub-tnangular
blotch of rose-red behind these on the centre of the back, and one on each side below the
dorsal tentacies. Branchice rather few, thickish, elliptic-oblong, nearly cylindrical, of a
yellowish olive-hrown, with numerous belts composed of granulated spots of dark olive,
sometimes indistinct. The apices pale; the whole of the external surface covered with
patches composed of opaque whitish spots. The branehi® are set along the sides in 6 to 8
rows of 3 or 4 papillse each: their size is nearly equal throughout. Foot watery white,
tapering to a fine point behind; the anterior extremity widened and rounded. Eyes small,
placed close behind the dorsal tentacles.
We know of no species with which this can be readily confounded. It is subject to some
slight variation in colour. Sometimes a specimen is found with the branchiae of a^rieher hue,
approaching to reddish brown, and sometimes of a much-darker or lighter tint, hut the modest
olive generally prevails. In a specimen found in Rothesay Bay, the papillm showed indications
of a brown ring at the apex. The spawn, which is deposited in the months of May and June,
forms a broad semicircular coil, attached to the under sides of stones. In the simple form of
the spawn and the single otolite of the auditory capsule, this species indicates the peculiarities
of the section of Eolis to which it belongs.
I
Fig. 1, 3, 5. Eolis olwacea of the usual colour.
2. The same, rich brown variety.
3. The same, dark, fall-coloured variety.
6, & 7. Papillse, more highly magnified.
8. Spawn.
(The figures in this Plate have inadvertently been reversed.)