498 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCLE'TY. 
DIGESTIVE SYSTEM. 
The following is the best method of dissecting out the 
alimentary canal :— 
1. Remove the funnel from the ventral surface of 
the head. 
2. Cut down the web between the two ventral arms, 
beginning anteriorly, and continue the cut down along 
the ventral surface of the head, thus exposing the Buccal 
bulb and the cartilage surrounding the brain. 
3. Loosen the intestine from the liver, dissecting 
out the ink sac from its place on the latter, so as to 
enable the intestine to be turned back. 
4. Loosen the liver at the sides, where it is connected 
to the cephalopedal muscles, by cutting through the 
visceral envelope, and then turn the liver forwards ~ 
(Pl. V, fig. 38a). The organs enclosed in the visceral sac 
are now exposed. Pl. LV, fig. 17, represents the alimentary 
canal, entirely dissected away from the surrounding 
tissues, to give a clear representation of the relations of 
the various parts. The alimentary canal is essentially a 
U-shaped tube, the ventral hmb of the U being the 
shorter, and the anus being approximated to the mouth. 
The Mouth is situated in the centre of the oral and 
anterior surface of the arms (Pl. II, fig. 5). It is 
circular, about 12 mm. to 22 mm. in diameter in large 
specimens, and is surrounded by a circular lip the edge 
of which is furnished with short finger-like papillae 
(Pl. IV, fig. 17, m.; Pl. Il, fig. 6, ¢.). — “Wihletesavenmaa 
surface of the lip is continuous with that of the web, and 
only marked off from it by a deep groove (fig. 6, gr,). 
This edge of the web forms a kind of contractile outer lip. 
The mouth leads into a cavity with very thick and 
muscular walls. This is the Pharynx and the oval 
