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Transactions. 



light, and this colour is due to these granules, which are yellowish-brown 

 in colour. They look like droplets of fat. Possibly this structure repre- 

 sents the hypobranchial gland, which, as Lang mentions, is absent in all 

 pulmonates except AmpMhola. This peculiar and striking phenomenon 

 was met with in every specimen examined. 



The heart lies at the base of the left side of the kidney : its wall is 

 formed of a thin, but tough, transparent membrane. The auricle is much 

 smaller than the ventricle, and broader posteriorly than at its anterior 

 end. Its wall is very thin, white, and but feebly muscular. The ventricle 

 is yellow in colour, and its wall is more muscular than that of the auricle. 



The lung {I) is situated between the kidney and the anterior muscular 

 edge of the mantle (fig. 3). The blood-vessels traversing it are not clearly 

 visible, on account of the fact that they have very large cavities and 

 extremely thin walls. Owing to the small size and very delicate walls 

 of the auricle I was unable to inject the lung through the auricle, but I 

 succeeded in injecting it through the pedal sinus, as will be described in 

 the account of the circulatory system. 



It is probable that dermal respiration plays as important a part as lung 

 respiration, and the thick layer of pigment covering the mantle in the 

 region of the lung may act as a respiratory pigment, as may also the 

 pigment covering the other parts of the body. 



Alimentary System. (Fig. 3.) 



The mouth [m) is placed between the two lappets of the head, and opens 

 into the cavity of the buccal mass. It is dark in colour, somewhat ovoid 

 in shape, the posterior portion being swollen. From the ventral surface 

 of this posterior portion the radula-sac extends backwards for a short 

 distance below the oesophagus. There is no jaw, nor did I find any trace 



Fig. 4. — Portion of the radula ( x 700). tc, central teeth ; tl, lateral 

 teeth ; tm, marginal teeth. 



of a rudiment of one. Two similar and symmetrical muscular masses pro- 

 ject into the cavity of the buccal mass in front of the radula, one on each 

 side of the middle line. They are dark in colour, and each is simply a 

 muscular thickening of the wall of its respective side. 



The radula is spatulate in shape, the pointed end being anterior. There 

 are forty-four rows of teeth, the rows being set obliquely to the median 



