MESSRS. HANCOCK AND EMBLETON ON THE ANATOMY OP DORIS. 249 
portion where it receives duct from testis ; g, point where it receives duct 
from androgynous apparatus ; h, opake part of mucus-gland ; i, semipel- 
lucid portion of same ; j, female channel leading to external opening ; 
A*, vagina leading to spermatheca /; m, duct from same to accessory 
spermatheca n ; o, duct from accessory spermatheca to oviduct. 
Fig. 6. Supposed immature spermatophora from testis of D. tuberculata. 
Fig. 7- Two spermatophora from spermatheca. a, one almost filled with irregularly- 
shaped cells ; h, another in which the cells have nearly all disappeared, 
containing innumerable spermatozoa. 
Fig. 8. Mature spermatozoa from spermatheca. 
PLATE XVI. 
Fig. 1. Side view of contracted heart of D.gilosa. a, ventricle; b, auricle; c, upper 
or dorsal wall of pericardium; d, floor of same; e, aorta; f, branchio- 
cardiac or efferent branchial vein ; g, portal heart. 
Fig. 2. Upper view of heart inflated, D. tuberculata, the pericardium laid open, with 
diagram of branchial circulation appended, a, ventricle; 6, auricle; c,e, walls 
of pericardium ; d, aorta ; e, e, two lateral veins coming from skin to 
auricle ; f, branchio-cardiac or efferent branchial vein ; g, outer or efferent 
circle, venous ; h, inner or afferent circle, arterial, at root of branchiee, 
within w’hich latter circle are situated the anal and the renal orifices; 
vessel passing from liver to branchise ; j, great efferent vessel from a 
branchial plume ; A-, afferent ditto ; I, anal orifice ; m, renal ditto. 
Fig. 3. Portal heart laid open, D. pilosa, showing pectinated laminse placed round 
the orifice leading to pericardium, a, lip of this orifice. 
Fig. 4. Side view of a pectinated lamina. 
Fig. 5. View of orifice leading into portal heart from pericardium, showing the inner 
margin beset with ends of pectinated laminae. 
Fig. 6. Side view of stem of branchial plume, D. pilosa. a, afferent branchial vessel; 
b, efferent ditto ; c, peculiar apparatus for the purpose of giving elasticity 
to breathing organ ; d and e, branchial leaflets. The arrows show the 
course of the blood. 
Fig. 7- Front view of portion of branchial plume showing its peculiar central appa- 
ratus, the vessels having been removed. 
Fig. 8. Cerebral nervous system, Z). a,a, cerebroid ganglia; A, A, branchial; 
c, c, pedial ; d, olfactory; e, buccal;/' gastro-oesophageal. 1, olfactory 
nerves ; 2, nerves supplying upper portion of channel of mouth and lip ; 
3, those to oral tentacles ; 4 and 5, to the sides and lower portions of 
channel of mouth and lip ; 6, optic nerves, each having at its origin a small 
ganglion ; 7, auditory capsules, the nerves being invisible ; 8 and 9, nerves 
2 K 2 
