94 NILS HJ. ODHNER, MOLLUSCA. 
musculature of the body sides. A very inconspicuous pleural ganglion (pl.) exists 
between them and the cerebral centra. At the hindermost side of the nervous ring, 
between the parietal ganglia, a very indistinct visceral centre (v.) is recognized by 
the visceral nerve (17) that emanates here near the right parietal ganglion and fol- 
lows the intestine backwards, till it ramifies in the hermaphrodite gland and the 
liver. — The whole under side of the posterior portion of the nerve centrum is 
occupied by the elongated pedal ganglia (p.). From their anterior end they send 
nerves to the foot gland (6), and from the posterior end a very strong nerve cord 
on each side stretches backwards innervating the foot and the hyponotum (10). — 
The statocysts were not observed. 
Fig. 50. Nervous system of Atopos australis(?): @ from below; 0 from right side; € from above. c. cerebral ganglia; 
oe. oesophagus; p. pedal ganglia; par. parietal ganglia; pl. pleural ganglia; v. visceral ganglion; J labial nerves; 2 tenta- 
cular nerves; 3 nerves to the musculature of the anterior body part; 4 nerves to the anterior part of penis; 6 buccal 
nerve; 6 nerves to the foot gland; 7 nerves to the anterior part of the foot; 8 nerves to the anterior parts of the body 
sides; 9 penis nerve (to posterior part of penis); 10 nerves to the posterior parts of the body sides; 
11 visceral nerve; 12 pallial nerve to posterior part of notum. 
The pallial organs (fig. 51). In the median line of the body, just under the 
end of the radular sac, the pericardium (p.) appears as an ovate bladder, and in it 
the light yellowish heart (h.) consisting of a posterior auricle and the ventricle in 
front of it. The pericardium was designated by Srrotn (1891) as a lung (cf. his 
figs. 19 and 21). In reality the lung is situated behind the pericardium and above 
the nephridium, something which is at once obvious from the fact that the auricle is 
turned against, and its blood-vessels intimately branched into, these organs. Their 
intimate connection seems to have caused SmmrorH to confound them when examining 
his sections. What Stmrorm has described as a mucus gland (»Schleimdriise») seems 
to correspond to an outer portion (J.) of the lung,’ for into this portion leads the 
' Pp. and F. Sarasin have found in this place a glandular expansion of the urethra, which they consider 
to be Smrorn’s »Schleimdriise». 
