68 Charles GELDERD 



sécrétion. Above the plateau is a cuticle which covers ail tlie cells of the digestive 

 gland cl. The tube is surrounded by a serous membrane Ly. D, X 3. 



FIG 46. Horizontal section through the pair of ventral tubes of the digestive 

 gland. The glandular ridges gL r. are seen throughout their entire length. In the 

 lower part of the ridge, the protoplasm of the cells has been entirely transformed, only 

 the fragments of their nuclei attached to the cell membranes remain n ; some of the 

 ordinary secreting cells contain vacuoles of secreted matter, others hâve burst leaving 

 only a cellular débris. 2/3 in, X 3. 



FIG. 47. A pair of tubes of the digestive gland of Macropsis seen in trans- 

 verse section. The glandular ridges gl r. in this species hâve a différent aspect. 

 They do not stand eut prominently in the tube. The ordinary secreting cells are 

 more elongated than in Macromysis. D, X '• 



FIG. 48. Transverse section of two tubes of the digestive gland of Siriclla. 

 This species contains several glandular ridges in each tube, in some of them the 

 process of vacuolisation is complète. 2/3 in, X 5. 



FIG. 49. Transverse section through some of the ordinary cells of the digestive 

 gland of Macromysis. The cells contain many vacuoles of différent sizes vc. The 

 large vacuole has . been emptied of its contents ; it is lined with a cuticle cl. A 

 smaller vacuole is forming at the side fuU of granules of proteid matter. The 

 minute vacuoles found in différent parts of the protoplasm of the cells contain each 

 a small granule. The cells are covered with a cuticle striated vertically. 1/12 Leitz, X 3. 



FIG. 50. Some of the cells of the glandular ridge. The cuticle and plateau 

 are seen on the internai surface of the cells. To the right the vacuoles are forming, 

 leaving the cell membranes attached to the plateau with a few protoplasmic fibres. 

 The elongated nuclei are closely packed together. 1/12 Leitz, X 3. 



FIG. 51. Ordinary cells of the digestive gland of Siridla. The nuclei contain 

 a large nucleolus. One of the cells has assuined a globular shape and is about to 

 be cast into the tube with its nucleus. 1/12 Leitz, X '• 



