178 ARTHUR WILLEY. 
Attention may also be drawn to the two arterioles which 
arise from the base of the right proventricular artery and 
supply the wall of the dorsal aorta. 
Fic. 23.—N. pompilius, g. Sketch to show the arteries which arise 
from the innominate arteries after the brain has been cut through. 4% a. 
Right tentacular artery, which gives off branches to all the tentacles of its 
side. The innermost or mesiad branch (o/f a.) supplies the bipartite 
laminated organ of van der Hoeven, which possibly represents a pair of 
inferior labial processes, and may have an olfactory function. fa. Infun- 
dibular artery, which passes through the cartilage into the funnel. The 
latter also receives minor branches from the columellar arteries. oc. a. Arteries 
to the eye. ped. a. Pedal artery, a convenient name for the common trunk 
from which the infundibular and tentacular arteries arise. opt. Optie gan- 
glion. cer. Brain cut across and drawn aside. a.c. a. Anterior columellar 
artery. a. p. a. Right anterior proventricular artery. Compare its origin in 
Fig. 7, where it arises from the aorta. d. a. Dorsal aorta. /. a. p. a. Left 
anterior proventricular artery, usually but not invariably present; it some- 
times arises from the left innominate artery, as indicated by the dotted lines ; 
and sometimes, as in this example, from the dorsal aorta. zz. Innominate 
arteries. d.a. Buccal artery. 7. m. a. Inferior mandibular arteries. 
