Structure and Development of tlie Nephridia. 405 



Figs. 51-54. These figures similarly represent four successive sections of the 

 terminal vesicle of the same nephridium. Large deeply staining gra- 

 nules are present in the walls of the vesicle, and in the adjacent 

 ectoderm of the body-wall. X 800. 



Fig. 55. Cross section of the terminal vesicle and adjacent glandulär region 

 of the 2a'i nephridium of the left side (somite VII) of the same larva. 

 The flattened cells of the vesicle with their contained excretory gra- 

 nules are shown. Also the early muscle-band crossing the vesicle at 

 its junction with the glandulär region. X 800. 



Fig. 56. Cross section through the anterior region of the nephridium of Fig. 55, 

 immediately behind the funnel. showing the nephridial blood-vessel, 

 with well-defined germ-cells (rudimentary ovary or testis) applied to 

 it. X 800. 



