ON NAUTILUS AND SOME OTHER ORGANISMS, iar 
Fic. 22.—N. pompilius, g. Dissection, from above, of the cephalic 
region to show the cephalic arteries. An incision has been made through the 
nuchal membrane, the hood, and the buccal membrane. The brain-capsule has 
been opened, and the median portion of the mantle behind the nuchal region 
has been removed. 0.c. Buccal cone. ent. inf. Dorso-lateral inner row 
of tentacles (the superior labial processes of Owen). 7. a. Labial arteries 
supplying the buccal membrane and fringe. s. m. a. Superior mandibular 
artery. s.7. Superior retractor muscles of the jaws (Owen). 4%. a. Buccal 
artery. 7@. m.d. Paired inferior mandibular arteries. 2. m. Nuchal mem- 
brane. a.c. a. Anterior columellar artery. a. p. a. Anterior proventricular 
artery. f. Dorso-posterior portion of funnel. 2. e. Free mantle-edges 
c. e. Cut edge of mantle. p.z.a. Pallio-nuchal artery. d. a. Dorsal aorta. 
cer. Brain with cerebral arteries. 2%. Cut edge of hood. 
N.B.—Apart from the cerebral arteries, all the anteriorly directed branches 
of the innominate arteries pass below the cerebral capsule. 
VOL. 39, PART 2,—NEW SER. M 
