EOLIS RUFIBRAN CIIIA L I S;.
EOLIS RUFIBRANCHIALIS, J ohnston.
E. gracilis, elongata, alb a: branchiis linearibus, coccineis, apicibus albis, in fasciculis 6-7 indis-
tinctis digestis : tentaculis dorsalibus corrugatis: angulis anterioribus pedis curtis.
Eolidia rufibranchialis, Johns., in Lond. Mag. Nat. Hist. v. 5, p. 428.
Idem., in Ann. Nat. Hist. v. 1, p. 121.
Eolidia Embletoni, Idem, in Loud. Mag. Nat. Hist. v. 8, .p, 379.
Hah. Under stones in pools at low-water mark, and in shallow water. Berwick Bay, Dr. Johnston.
Whitley and Cullercoats, rather rare. Lamlash Bay, Rev. D. Landsbormgh.
Body about an inch long,‘very slender, and tapering to an exceedingly fine point; transparent
watery white, appearing yellowish in the centre, from the viscera shining through; an
opake white line passes along rfie ridge of the hack from the heart to the end of the tail.
Dorsal tentacles moderately long, tapering, wrinkled transversely, and set at a little'distance
apart; of a yellowish white, sometimes tinged with rose colour, and having an opake line of
white oh the upper part of the posterior surface. Oral tentacles of about an equal length
with the dorsal pair, transparent white, with an opakewhite central line; rather depressed
and separated by the rounded outline of the head. Bronchia rather short, slender, nearly
linear; the central vessel scarlet or rose red, with the margins much undulating ; the sheath
transparent, and having a slender opake white ring near the apex< They are set in six, or
seven iH-defined clusters on the sides of the hack ; and are arranged in transverse rows, the
largest containing about four papillae each: in the first cluster there are six or seven rows;
in the next, four; and two or three each in the others. Foot very transparent, dinear, and
extending considerably beyond the branchiae into a very slender point behind ; in front the
margin is slightly bilobed, slit transversely, and a little produced at the sides, ending in small
points.
This is one of the most slender and delicate forms of the genus. It is met with
on the rocks near low-water mark in April, May, and June, when it has attained its
full growth, and is spawning. The spawn is attached to the under surface of stones in
pools, and resembles that of E . cororiata, but is more openly coiled, and the band or thread
of eggs is less undulated. In August and September, the young are found considerably
advanced.
This beautiful species has been much misunderstood. We agree with Dr. Johnston in
uniting his E . Embletoni and E . rufibranchialis, yet we suspect that he has included more