MR. A. HANCOCK ON THE ANATOMY OF DORIDOPSIS. 205 
Fig. 2. View of the stomach, laid open, of D. gemmacea, showing the reticulated character of its walls: 
a, liver; b, posterior lobes of ditto; c, ovary ; d, cesophagus or anterior stomach ; e, intestine, 
laid open; „f, large fold of the mucous membrane of ditto; g, cavities or cells in the wall of the 
stomach. 
Fig. 3. View of the anterior portion of the alimentary tube of D. gemmacea: a, portion of the peritoneal 
membrane; 5, ductless gland connected with the blood-system; c, anterior portion of the 
aorta, giving a bránch to the enlarged division of the proboscis; d d, two glands opening into 
the anterior extremity of the proboscis; e, cerebral ganglia; f/f, nerves given off from ditto ; 
g, one of the buccal ganglia; 4, commissure connecting ditto with the cerebroid ganglia ; 
i, one of the cesophageal nerves; j, posterior wall of the sac or sheath of the proboscis ; 
kkk, retractor muscles of ditto; l, anterior portion of the proboscis; m, posterior or enlarged 
portion of ditto; n, cesophagus or anterior stomach ; 9, salivary gland. 
Fig. 4. The so-called pericardium of D. gemmacea, laid open, showing the ventricle and auricle, the 
latter likewise laid open: a a, dorsal wall of the pericardium, turned back ; 4, laminæ at the 
anterior margin of ditto; c, ventricle; d, auriculo-ventricular orifice; ee, wall of the auricle, 
laid back; f, fleshy columns of ditto; gg, openings of the great lateral pallial trunk vein or 
' sinus; 4, small orifices leading apparently into the skin; 2 i, branchio-cardiac channels, leading 
from the efferent branchial channel ; j, efferent branchial channel; k k, openings of the lateral 
portions of ditto ; /, orifices of the branchial veins; m, pyriform vesicle, bulging through the 
floor of the so-called pericardium ; 2, orifice of ditto, opening into the pericardium ; o, branchial 
plumes. 
PLATE XVII. 
Fig. 1. View of the alimentary system of D. gemmacea, the other viscera having been removed: a, ante- 
rior extremity of the animal; 5, branchial plumes; c c; dorsal skin ; d, posterior wall of the 
sac or sheath of the proboscis; ee, retractor muscles of ditto; f, minute muscular bands to 
regulate the movements of ditto; g, anterior portion of the proboscis; A, posterior or enlarged 
portion of ditto ; i, one of the salivary glands; j, two glands opening into the anterior extremity 
of the proboscis; k, duct of ditto; /, esophagus or anterior stomach; m, liver; n, posterior 
lobes of ditto; o, intestine; p, anal nipple; g, renal orifice; r, pyriform vesicle in connexion 
with the renal organ; s, ovary; ¢, oviduct; u, enlargement of ditto; vv, hepatico-branchial 
vein, laid open; w, branch from aorta; 2, one of the buccal ganglia; y, one of the cesophageal 
: nerves; z, external opening of the reproductive organs. 
Fig. 2. Anterior portion of the alimentary tube of D. gemmacea, laid open: a, portion of the anterior skin 
of the animal; 5, sac or sheath of the proboscis; c, posterior wall of ditto, partially invaginated ; 
d d, two of the retractor muscles of ditto; e, oral opening ; f, orifice of the proboscis, with the 
margin thickened; g, anterior portion of the proboscis; A, posterior or enlarged portion of 
ditto, exhibiting three or four longitudinal areas in the inner surface, continuous with similer 
areas of the anterior portion ; i, two glands opening into the anterior extremity of the proboscis ; 
Jj, duet of ditto; k, enlargement of the duct; l, orifice of ditto; T, ridges immediately in 
front of the orifice; m, œsophagus or anterior stomach, exhibiting the corrugations of the inner 
Fig. 3 — nn, salivary glands. HERE 
'*. Anterior extremity of the proboscis, showing the continuation of the duct of the two glands 
through its wall: a, thickened margin of the orifice of the proboscis; b 5, ridge, the homologue 
of the buccal lip in Doris; c, duct; d, orifice of ditto, leading into the proboscis. 
The so-called pericardium of D. nigra, laid open: 4 4; dorsal wall of the pericardium; 6, laminæ 
a. anterior margin of ditto; c c, liver, seen through the floor of ditto; d, ae ditto ditto ; 
Fig. 4, 
