130 AMPHORINA COERTJLEA.
A slender, elegant animal, which may attain a length of 15 mm., but is generally
much smaller. The details of its gorgeous coloration are somewhat differently described
by different authors, and probably vary according to the light and position in which the
animal is seen. The body varies from greenish yellow to orange and this same tint is
maintained in the oral tentacles and rhinophores, but the cerata are marked with bands of
blue and brilliant yellow or orange red and have pale tips. Respecting the colour of the
animal Mr. Beaumont observes (Beaumont 1, pp. 837—838) : “ The description of the
papillae in this species given by Alder and Hancock (loc. dt.) is wanting in the accuracy
uSual with those authors. They say, ‘ Central gland . . . green below and dark
blue above ; outer surface of the papilla above pale blue, below pale green ; a few yellow
freckles in front ; tips strongly capped with orange red, banded below with a ring of
bright yellow; extreme points colourless and pellucid.’ In point of fact the hepatic
cæcum is dark bottle-green throughout, the brilliant metallic blue colour of the middle
part of a papilla being entirely due to reflection from small flecks of opaque superficial
material. Above and below the blue there is usually a band (often incomplete posteriorly)
of yellow or orange, also superficial ; and near the tip of the papilla the cnidogenous sac
shows through yellow, orange, or sometimes crimson. The general colour of the sheath
is pale, transparent green. The extent of the blue and yellow or orange colour is subject
to much variation in different individuals, and in the different papillæ of the same
individual ; often some of the opaque material appears white by reflected light, especially
when the background of dark green afforded by the hepatic cæcum is lacking. Prof.
Herdman’s description of the papillæ of Æ. molios is somewhat vague ; there appears in
his account of the species very little reason, as I think, to separate it from A. coerulea.”
The foot is fairly broad, and the corners are produced into small prolongations. The
oral tentacles are short, but the rhinophores very long, smooth, and straight. The cerata
are cylindrical, moderately long, and set in five to nine groups. The first group is the
largest and contains seven to ten cerata ; the others decrease progressively towards the tail
and contain only five, four, three; or two.
The jaws bear a single line of denticlés. The long radula1 consists of a single series
of sixty to eighty teeth. They are of the horse-shoe shape and rather broad ; the lower part
of each side limb is expanded. They bear a central cusp, and on either side five to seven
(usually six) denticles. The central cusp, though long, rises far back and points upwards
more than usual, so that its proportions are not clearly visible. The radula tapers in a
remarkable manner, the hinder teeth being at least twice as broad as those in front. This
phenomenon seems due to the persistence of the older and smaller teeth, which do not drop
off as quickly as in other genera.
The penis is armed with a long, straight, chitinous tube.
1 In their Synopsis (Pt. vii, p. 51) Alder and Hancock class Eolis coerulea under the heading
Lingual plate with large denticles and a stout central spine. Two sepa/rate plain lateral plates. But
it is clear that in this and several other instances the position accorded to a species in the synopsis
cannot be accepted as evidence of the character of the radula, unless there is proof that Alder and
Hancock examined tlie radula. In the present case they had not seen a specimen of E. coerulea
when they wrote the Monograph (see Appendix, p. xi), and the position given it must represent a
mere guess.
AMPHORINA COERULEA. BÜ
Vayssidre has described the spawn, which is short and shaped like a crescent, with
the two horns turning inward, and Trinchese has given some particulars of the early
development of the ova.
CUTHONA (?) NORTHUMBRICA A. & H.
(Plate VI, figs. 4 and 5.)
There remain of this species four figures by Hancock, one of which is similar to the
drawing of the whole animal in the Monograph but not so good; one is a rough drawing
of a rhinophore, and two are reproduced here. With the figures are notes to the effect
that two specimens were captured on Cullercoats Rocks on April 11th, 1861. There
follows a description of the living animal which is practically identical with that in the
Monograph, except that the papillae are said to be set in ten or eleven rows, with five
papillas in the larger rows. Hancock adds: “ The figure in the plate (i. e. plate 31, fam. 3
of the Monograph) is pretty correct. There can be no doubt about the species.
The original description is very correct.” I t would appear that fig. 4 in Plate VI of the
present series was drawn from a living specimen but fig. 5 from a dead one.
No further specimens of the animal have been found since the time of Alder and
Hancock, and as the anatomy is unknown the genus remains uncertain.
; CUTHONA (?) INORNATA A. & H.
(Plate VI, fig. 3.)
Alder 1, pp. 46—47.
The drawing is by Alder. The animal is briefly described .in the Appendix to the
Monograph,, p. ix (25), where it is suggested that it may be a variety of AEolidia
papillosa. But the stout cylindrical papillas hardly support this suggestion, and the
classification in the Synopsis (pt. vii, p. 50) which places it with E. olivacea and E.
aurantiaca is more probable. The animal has not been seen since the time of Alder and
Hancock, and without further examination it is impossible to say to what genus it is
referable.
JSOLIDIELLA ANGULATA (A. & H.).
f = AE. glauca var.
See Eliot 1, pp. 357—358.
Mr. C. W. Walton informs me that he considers a specimen which he captured near
Plymouth to be undoubtedly the same species as that figured in the Monograph under
the name of Eolis angulata, and has kindly supplied me with the following notes on the
appearance of the living animal and on the radula: