The hepatic ducts are two, and open close together into the commencement of the pyloric cœcum. They have developed upon them the light-coloured spongy “pancreatic” glands, which show under the microscope a loose fibrous tissue interspersed with yellow concretions (fig. 4). The fibrillar tissue is more loose and the yellow concretions larger, but less numerous, than in the liver. There is everywhere a network of ramifying tubes. The whole of the organs are enclosed in a peritoneal membrane, which sends three mesenteric reflexions to the mantle, one of the arterial branches from the posterior aorta running along the anterior border of each reflexion. Nervous System. The main masses of the nervous system are aggregated into a large circular band (pl. vii., fig. 1 d) surrounding the gullet and lying in the aperture of the cephalic cartilage. On the anterior side of the gullet lie the cerebral and superior buccal ganglia, almost confluent and on the posterior surface are the inferior buccal, pedal, and parieto-splanchnic ganglia. The cerebral ganglion sends off optic nerves which enlarge greatly, forming the optic ganglia (pl. vii., fig. 1 e). I have not been able to discover the auditory nerves. From the parieto-splanchnic ganglia two nerves run, one on each side, towards the anterior aspect of the animal, passing under the columellar muscle and each forming on the back of the pallial chamber and at the side of the gladius a large stellate ganglion (fig. 1 g), which sends branches over the mantle. For about half their course the nerves to these ganglia are imbedded in the liver. On the intestine, at the point where the pyloric cœcum is given off is a well-marked ganglion (fig. 1 l), which appears to be connected with the main nervous centres by a nerve following the course of the intestine. This ganglion gives off radiating fibres on all sides. Eyes. The eyes are lateral, are large and prominent and are covered by a transparent layer of integument. The eyeball is invested by a silvery tapetum composed of loose cells in two layers, one or both of which contain numerous refracting corpuscles. In front this passes into the loose iris, but I have not been able to observe any cartilage of the iris. The tapetum is lightly attached and can be easily removed. Then comes a thin, transparent, apparently muscular membrane, covering a thin cartilaginous coat which becomes thickened slightly in front. The membrane is not continued beyond the thickened front edge of the cartilaginous coat. Within the opening is suspended a cartilaginous ring, to which is attached a fringed radiating membrane having the lens in its centre. This is the corpus