bound food material is picked up from the foot by the jaw-plates, the radular teeth are erected, and their sharply pointed cusps rake the food inside the mouth. Here it is passed backward by ciliary currents along the glandular dorsal region of the pharynx. The pharynx (Fig. 1, PH.) has the usual structure—a stout ovoid bulb with an odontophore supported by paired cartilages. The radula caecum is small, projecting only a short distance through the pharynx floor. Its recurved tip (Fig. 1, R.CM.) rests just beneath the base of the oesophagus. Tiny paired salivary glands (Fig. 1, S.G.) open through the pharynx roof at the beginning of the oesophagus. They are visible in dissection as diffuse whitish lobules, and their tubules are without lumina, with mucous cells containing a light-staining secretion, but with no trace of enzyme-producing cells. The ducts are short and narrow (150μ) with ciliated cells sparsely distributed between stouter gland cells.

The oesophagus widens behind the nerve ring to form a spacious, thin-walled tube (1 ½mm. in diameter) with impermanent longitudinal folds. Two ridges are, however, more constant, bounding the dorsal food-conducting tract leading from the pharynx and passing down the left side of the oesophagus at the site of visceral torsion. The food tract finally passes backwards along the oesophageal floor, remaining distinct with taller lateral folds for two-thirds the distance to the stomach. Posteriorly the oesophagus becomes narrower (½mm.) and its epithelium is thrown into a series of more permanent folds, with very distinct ciliary currents leading along the summits towards the stomach. As in other style-bearers there remain no traces of the ventral glandular pouches of the anterior oesophagus. The cells of the morphologically dorsal food tract are taller (50μ), but the whole lining epithelium is uniformly ciliated and glandular, with mucous cells staining lightly with haematoxylin, and forming by their secretion the oesophageal food string.