PLATE Y. 
Fig. 1. Pneumonoderma. 
Fig. 1. Dorsal view of the central nervous system; a, cerebral ganglion; b, pedal ganglion; c, pleural 
ganglion ; d, visceral ganglion'; e, cerebro-pedal connective ; /, cerebro-pleural connective ; g, 
pleuro-visceral connective ; h, olfactory nerve ; i, optic nerve ; j, nerve to the acetabuliferous 
appendage ; k, nerve to the anterior tentacle ; l,' labial nerve. 
Fig. 2. Dolabellq neapolitana. 
Fig. 2. Central nervous system, seen from the right side ; a, cerebral ganglion ; b, pedal ganglion ; c, pleural 
ganglion ; d , right visceral ganglion ; e, cerebro-pedal connective ; f, cerebro-pleural connective ; 
g, pleuro-visceral connective ; h, oesophagus. 
Fig. 3. Spongiobranchsea. 
Fig. 3. Central nervous system seen from the left side ; a, cerebral ganglion ; b, pedal ganglion ; c, pleural 
ganglion ; d, left visceral ganglion ; e, cerebro-pedal connective ; /, cerebro-pleural connective ; 
g, pleuro-visceral connective ; h, otocyst ; i, auditory nerve ; j, cerebro-buccal connective ; 3, genital 
nerve; 4, lateral nerve. from the left visceral ganglion. 
Fig. 4. Clione limacina. 
Fig. 4. Ventral aspect of the anterior portion; a, evaginated proboscis; b, evaginated book-sacs; c, buccal 
cone ; d, anterior tentacle ; e, fin ; f, lateral lobe of the foot ; g, posterior lobe of the foot. 
Figs. 5-7. Clione. 
Fig. 5. Anterior region, seen from the right side, in order to show the visceral openings ; a, anterior tentacle ; 
b, head ; c, foot ; d, fin cut off at its origin ; e, anus ; /, aperture of the kidney ; g, genital 
aperture ; h, spermatic groove ; i, orifice of the penis ; j, osphradium. 
Fig. 6. Osphradium and its nerve supply, seen from the right side ; a, cerebral ganglion ; b, pedal ganglion ; 
c, pleural ganglion ; d, right visceral ganglion ; e, osphradium ; /, oesophagus ; g, anus ; h, opening 
of the penis ; i, lateral lobe of the foot ; j , posterior lobe of the foot. 
Fig. 7. Transverse section of the osphradium; a, osphradial nerve; b, its sheath, continued by the connective 
envelope of the osphradium ; c, ganglionic cells of the osphradium ; d, sensory epithelium. 
Figs. 8-11. Halopsyche gaudicliaudi. 
Fig. 8. Ventral aspect of the central nervous system; a, cerebral ganglion; b, pedal ganglion; c, right 
visceral ganglion ; d, posterior visceral or abdominal ganglion ; e, left visceral ganglion ; /, second 
pedal commissure ; g, cerebral commissure ; h, cerebro-pedal connective ; i, otocyst ; j, nerve to 
the buccal appendage ; k, nerve and ganglion of the nuchal tentacle ; l, nerves to the fin ; m, nerve 
to the foot ; 1, 2, 3, 4, visceral nerves. 
Fig. 9. Oral view of the central nervous system ; a, cerebral ganglion ; b, pedal ganglion ; c, buccal ganglion ; 
d, cerebro-pedal connective ; e, cerebro-buccal connective ; /, second pedal commissure ; g, nerve 
and ganglion of the nuchal tentacle ; h , nerve to the buccal appendage ; i , nerve to the foot ; 
j, nerves to the fin. 
Fig. 10. Central nervous system, seen from the left side; a, cerebral ganglion; b, pedal ganglion; c, left 
visceral ganglion ; d, posterior visceral ganglion ; e, nerve to the buccal appendage ; /, nerve and 
ganglion of the nuchal tentacle ; g, nerv.es to the fin ; h, otocyst ; 3, 4, visceral nerves. 
Fig. 11. Transverse section of the central nervous system passing through the visceral ganglia; a, cerebral 
ganglion ; b, right visceral ganglion ; c, posterior visceral or abdominal ganglion ; d, left visceral 
ganglion ; e, cerebral commissure ; /, oesophagus. 
