556 W. A. HERDMAN AND J. A. OLUBB. 
EXPLANATION OF PLATES XXXII, XXXIII, and 
XXXIV, 
Illustrating Messrs. W. A. Herdman’s and J. A. Clubb’s paper 
“On the Innervation of the Cerata of some Nudi- 
branchiata.” 
The figures were drawn from the sections, as seen under Swift’s 1-inch 
(x 50) and +-inch objectives (x 300), with the occasional use of Zeiss’s 
=4,-inch oil immersion for the more minute details. ‘The following abbrevia- 
tions are used for the reference letters : 
6. m. Buccal mass. 4. . Body-wall. 47. Branchie. 46. s. Blood-sinus. 
6. c. Blood-corpuscles. Jduc.g. Buccal ganglion. cer. g. Cerebral ganglion. 
c. Hepatic cells. c.¢, Connective tissue. c.m. Circular muscles. cz. ¢. 
cnidocyst. cz. s. Cnidophorous sac. ep. z. Epipodial nerve. ¢. Hye. ec. 
Ectoderm. f. Foot. gi. Glands. 4. c. Hepatic cecum. /. m. Longitudinal 
muscles. 7. Liver. m. Muscle-fibres. 1. c. Nerve-cell. 2. sh. Nerve- 
sheath. @s. @sophagus. 0. ¢. Ovo-testis. 0. c. Otocyst. p.g. Pedal 
ganglion. pl. g. Pleural ganglion. p.. Pedal nerve. 7. Part of radula. 
r, a. Reproductive aperture. vez. Renal organ. s¢. Stomach. sf. Sheath of 
ganglion or nerve. 
PLATE XXXII. 
Fic. 1.—Transverse section of Polycera quadrilineata at level of 
eye (section 81 of series), showing relation of cerebral ganglia (c. g.) to 
buccal mass and body-wall, and the anterior loop of the epipodial nerve 
(ep. m.). xX 50. 
Fie. 2.—Another transverse section of same series, ten sections further 
back, in region of reproductive aperture, showing cerebro-pleural and pedal 
ganglia, with the origin of the epipodial and of various pedal nerves, and 
also the epipodial nerve in section in its course backwards. x 50. 
Fie. 3.—Dorso-lateral part of another transverse section of the same 
series (No. 166), in the region of the branchiz, to show the epipodial 
nerve ‘in the body-wall over the edge of the ovo-testis, and a branch of it 
entering one of the ceratal processes. x 300. 
Fic. 4,—Transverse section (No. 106) of Ancula cristata, showing the 
three pairs of ganglia surrounding the cesophagus. x 50. 
Fic. 5.—Part of adjoining section, showing the ganglia more highly mag- 
nified. x 300. 
