GONIODORIS.
(5), which are sessile on the outer margin above, of the cerebroid portion of the upper ganglia.
The auditory capsules contain numerous otolithes, and are seated upon the under surface of
the upper ganglia, near to their junction with the pedial.
The buccal ganglia (<?, e) occupy their usual position on the buccal mass, immediately
behind the oesophagus: they are elliptical, are united across the median line by a longer
commissure than usual, and are joined to the upper ganglia by two fine cords {h, h).
These ganglia give nerves to the tongue (15), and buccal organ (13,14), and have attached to
them by longish pedicles a pair of gastro-cesophageal ganglia, (ƒ,ƒ), which send two nerves
(16) down the oesophagus, and also supply the salivary glands.
The only traces that we have detected of a sympathetic system are the oesophageal nerves,
and the small ganglia, and some minute nerves on the root of the intromittent organ.
The skin is soft and more or less tuberculated; and though well supplied with spicula,
they are not sufficiently numerous to stiffen the surface.
EXPLANATION OF THE PLATE.
Fig. 1. General view of the viscera of Goniodoris nodosa, partially spread out and seen from above
a, buccal mass; b, buccal gizzard; c, c, salivary glands; d, oesophagus; e, upper portion of
stomach; f fiver mass; g, g, intestine ; h, retracted penis; i, tubular portion of testis; i',
glandular portion of the same; i", small tubular or duct-like portion of the same ; j, portion of
oviduct as it leaves the ovary; ƒ , dilated portion of the same; k, k, ovary overly ing the fiver; l,
mucus-gland of female organs; m, vaginal tube, leading from the exterior to the spermatheca;
n, spermatheca; o, tube leading from the same to the oviduct; p, accessory spermatheca; q,
pericardium; r, ventricle, seen through the transparent walls of the pericardium; s, auricle ;
t, t, lateral trunk-veins from mantle to auricle; u, branchio-cardiac vein; w, portal heart,
seen through the transparent membranes of the h eart; a?, branchial plumes; y, renal o rgan;
z, cerebral ganglions.
2. Front view of the prehensile collar of Goniodoris nodosa:—a, collar; b, membranous fringe
attached to the inner margin of the same; c, buccal lip ; d, buccal orifice.
3. A few of the spines from the prehensile collar of Goniodoris nodosa.
4 . Cerebral ganglions of Goniodoris nodosa:—a, a, cerebroid and branchial ganglions fused into
two masses; b, b, pedial; c,c, olfactory; d, visceral; e, e, buccal; ƒ, f , gastro-cesophageal; g,
great oesophageal collar; h, h, nervous cords connecting the buccal ganglions to the cerebroids;
i, small collar uniting the branchial and visceral ganglions; 1, olfactory nerves; 2, nerves
supplying the upper portion of the channel of the mouth; 3, those to the side of the oral
channel and oral tentacles; 4 , those to the under side of the channel of the mouth; 5, eyes,
each seated on a small ganglion; 6, pallial nerves; 7, a nerve which goes to a small ganglion
( j ) seated on the root of the male intromittent organ; 8,9,10, pedial nerves; 11,12, visceral
nerves; 1 3 ,14, buccal nerves; 15, lingual nerves; 16, oesophageal nerves.
5. Front view of the rudimentary prehensile collar of Idalia pulchella :—a, spinous lobes; b,
buccal lip ; c, oral opening.
6. Two spines from the same highly magnified.
7. Front view of prehensile collar of Ancula cristata:—a, upper margin.
8. A few of the spines from the same much enlarged.
GONIODORIS.
Fig. 9. General view of the. viscera of Polycera quadrilineata, the dorsal skin being laid open and the
various organs a little sep ara ted—a; buccal mass; b, salivary glands; *c} oesophagus; d,
upper wall of stomach; e, intestine; ƒ, v en t; g, fiver mass enveloped in the ovary; h,
retracted penis; i, glandular portion of testis; tubular portion of the same; i", constricted
tubular portion; i'", short tube uniting the glandular portion to the oviduct; j , oviduct as it
leaves the ovary ; f , dilated portion of the same; k, mucus-gland in connexion with female
parts; l, vaginal tube leading from the exterior of the spermatheca; m, spermatheca; n, tube
from the same to the oviduct; o, accessory spermatheca; p, ventricle of the heart, turned
forward; q, a portion of the auricle; r, arterial trunks; s, cerebral ganglia; t, branchial
plumes.
10. External view of one of the jaws of Polycera quadrilineata:—a, cutting edge; b, upper
margin.
11. Jaws of Polycera Lessonii, as seen in the compressor of the microscope, the buccal mass laid
open from below:—a, buccal lip; b, jaws; c, point of articulation; d, cutting edge.
12. Cerebral ganglions of Polycera quadrilineata:—a, a, cerebroid ganglions; b, b, branchial; c, c,
pedial; d, olfactory; e, visceral; f , buccal; gfg, commissural cords connecting the buccal
ganglions to the cerebroids; h, small collar uniting the branchial and visceral ganglions ; i,
great oesophageal collar; 1, olfactory nerves terminating in ganglionic enlargements ( j )
within the tentacles; 2, nerves to the oral tentacles; 3 and 4, those to the channel of the
mouth; 5, optic nerves, each having at its origin a small ganglion; 6, nerves supplying
tentacular filaments and dorsal skin in front; 7, pallial nerves; 8, a nerve to the skin on the
side of the body; 9,10, 11, pedial nerves; 12, 13, buccal nerves; 14, lingual nerves; 15,
oesophageal nerves; 16, 17, 18 visceral nerves.
13. Buccal mass of AEgirus punctilucens, side view r—a, channel of the mouth ; b, oesophagus;
c, lingual sheath; d, d, salivary glands; e, glandular organ, supposed for secreting mucus to
lubricate the foot.
14. Front view of buccal mass of the same, the channel of the mouth having been removed :—
a, buccal lip; b, oral opening; c, lingual sheath; d, upper corneous jaw, or tooth; e, lateral
membranous fringes.
15. Corneous jaw or tooth of AEgirus punctilucens removed from the buccal lip :—a, cutting edge
with median denticle. «