Farnie. — The Structure of Ampliibola crenata Martyn. 77 



These entochlorophyll granules are just as numerous in a fasting animal 

 as in one that has been feeding. The only difference I found was that the 

 granules from a fasting animal dissolved in caustic potash at once ; those 

 in the other animals took a long time, some of them not dissolving at all. 



Schneider (1902) distinguishes three kinds of cells in the liver : (a) liver 

 cells, (&) excretory cells, (c) lime cells. 



According to him, two sorts of granules occur in the " liver cells " — 

 small liver-granules, which stain red in eosin, and large excretion granules 

 (entochlorophyll). The " liver cells." he says, perform a nutritive and 

 secretory function. The " excretory cells," he says, stain a deep black in 

 osmic acid. The " lime cells " contain phosphate of lime. 



The liver cells, as I have described, are present in the liver of Amphi- 

 hola, I tested for " excretory cells " with osmic acid, but obtained no 

 result ; and of " lime cells " I could find no trace. 



MacMunn (1900) regards the cells containing entochlorophyll in molluscs 

 as " ferment cells." He also describes " lime cells," but finds no trace of 

 the so-called " excretory cells." He tested for glycogen in the liver, but 

 obtained no results. Nor have I found any trace of glycogen in these cells 

 in Amphibola. 



The Nervous Sy stein. (Fig. 5.) 



The nervous system consists of a ring of nerve-tissue surrounding the 

 buccal mass a short distance from its posterior end. The ganglia are 

 bright-orange in colour. 



The cerebral ganglia are connected by a fairly stout cerebral commissure. 

 From each there passes backwards and downwards a slender connective to 

 the buccal ganglia, which are, as usual, of small size, and are situated 

 slightly behind the entrance of the salivary gland. From the buccal 

 ganglia, whicli are joined by the commissure, small nerves are given off 

 to the buccal mass. 



From each cerebral ganglion the following five nerves are given off to 

 the anterior region of the head : («) A very fine nerve, which runs along- 

 side and close to the buccal mass, innervates the head lappet in the region 

 of the mouth ; (6) to the outer side of this is a nerve which almost at once 

 bifurcates ; (c) a very fine nerve, and {d) a stouter one which bifurcates 

 (these two run parallel with the posterior branch of nerve b) ; (e) the two 

 tentacular nerves run outwards and slightly upwards to enter the base of 

 each tentacle, and one of the two innervates the eye. 



From the right ganglion there also arises a stout nerve (/) which runs 

 outwards and backwards and then bifurcates, the two branches supplying 

 respectively the anterior and posterior portions of the penis. There is no 

 corresponding nerve on the left side of the animal. 



The pleural ganglia lie on the body- wall close to the cerebral, to whicli 

 each is connected by the cerebro-pleural connective. There are apparently 

 no nerves given off by these ganglia, but from the right pleuro-pedal con- 

 nective, and nearer to the pedal than to the pleural ganglion, a slender 

 nerve is given off which bifurcates almost immediately ; the anterior 

 branch (g), crossing below the penis, goes to the anterior end of the common 

 genital duct, the posterior supplies the body-wall. On the left side the 

 corresponding nerve, which also bifurcates, is, of course, entirely limited 

 to innervating the body-wall of this side. 



The pedal ganglia are of about the same size as the cerebral ; the 

 pleuro-pedal connectives are very short. From the pedal ganglia several 

 large nerves supply all regions of the foot. 



