| OCR Text |
Show 676 MR. J. GRAHAM KERR ON THE [June 18, series of tentacles, separated by a peculiar lamellated organ which has been supposed to be sensory. This lobe is called the "inner inferior lobe" by Lankester. For its innervation there is figured by Owen, and copied by Gegenbaur and others, a small distinct ganglion on each side. In the specimens which I have dissected, however, the conditions are as follows :- Upon each side, somewhat external to the root of the funnel-nerve, there arises from the anterior sub-cesophageal nerve-Cord a rather thinner nerve-trunk, which passes into the basal part of the lobe mentioned. This bends towards the middle line, pursues a curved course in the substance of the lobe, and meets with its fellow of the opposite side. The two together form in fact not two separate ganglia, but a continuous cord. The median most strongly curved part of this cord gives off about 24 slender nerve-filaments, which radiate forwards to the lamellae of tbe lamellated organ. The more lateral parts of the cord, on the other hand, give off a stout unbranched nerve to each of the tentacles of the lobe. These nerves, coursing as they do through the fibro-muscular substance of the lobe, are very hard to trace out in tbeir entirety. VI. The Post-anal Papillce and Nerves. A short distance behind the anus is a peculiar flap-like structure, arising from the body-wall and bearing four papillae. It varies Fig. 5. Post-anal papilla with glands in the female. a, anus; p.a.p, post-anal papilla ; g, openings of glands ; n.g, nidamental gland ; p.c.v, pericardio-visceral aperture; neph, opening of kidney chamber. |
