CH. VII] SNAILS AND SLUGS 219 



is capable of emulsifying fats. There are also found in it 

 hsematin and a product of the decompositions of chloro- 

 phyllaceous food termed " entero-chlorophyll." In the 

 gland itself Barfurth 1 distinguished ferment-, lime- and 

 liver-cells. Mac Munn 2 has shown that granules may be 

 present both in ferment- and in liver-cells and regards the 

 granules as being entero-chlorophyll. In this he is 

 supported by Miss Newbegin 3 , who however holds that the 

 excretion of the granules is the work of the epithelium of 

 the intestine. By Biederrnann and Moritz 4 tHe granular 

 (liver) cells are regarded as absorptive, this function being 

 but sparingly performed by the intestinal epithelium. In 

 view of results obtained by other investigators of the 

 functions of the digestive glands of other invertebrata, 

 there is much probability in the accuracy of this view. 

 Glycogen is found in the connective tissue cells of the 

 gland in Helix and in the granular (liver) cells themselves 

 in Limax. The amount of lime present in the digestive 

 gland varies at different seasons. Barfurth found that in 

 the digestive gland of H. pomatia the percentage of 

 inorganic ash averaged 20*24 in May, 25*72 in September, 

 10*26 in winter after the formation of the epiphragm, and 

 16*99 after the breaking and repair of the shell. It is 

 clear then that in addition to its other functions the gland 

 serves as a storage organ for calcareous matter. The 

 faeces are extruded at the anus by the action of a longi- 

 tudinal band of muscle upon the outer side of the rectum : 



1 Op. dt. 



2 Phil. Trans, cxcin. B. 



3 Q. J. M. S. XLI. ; and Zool. Anz. xxn. 



4 Pfliigefs Arch. f. ges. Physiol. LXXV. 



