Fig. 33. Enlarged drawing of the left organ of Claus shown in Figure 27. 

 The nature of the basal plates is shown to some extent. X 665. 



Fig. 34. Sagittal section of the left organ of Claus shown in Figure 27. The 

 plane of section is indicated by the line of a, (3 in Figure 33. 

 The depth of the structure is revealed by Figure 34, but was 

 not brought out in Figure 33. X 665. 



Fig. 35. Semi-diagrammatic drawing of frontal section of brain and part of 

 the circumoesophageal commissures. Mallory's connective-tissue 

 stain. To show relations within the brain of organs of Claus, 

 nerves and neuropil masses, as well as nerve fibres. This section 

 should be compared with the sagittal section shown in Plate 1, 

 Figure 4. X 270. 



Fig. 36. Cross-section of an organ of Claus. Vom Rath's fluid 18 hours. In- 

 serted to show shape of basal plates in deeply blackened prepara- 

 tions, and the mutual arrangement of the two cells, and their 

 granules and interior bodies. X 665. 



Fig. 37. Frontal section of organ of Claus seen from dorsal side. Vom 

 Rath's fluid IS hours; decolorized. It shows the line of contact 

 betweeia the cells of the organ, and the arrangement of granules 

 and of interior bodies. X 665. 



