HERPETOMONAS ELMASSIANI. 



333 



short distance. In the two pink portions, granular and frothy, 

 red clouds were also visible just at the same point. 



Until the gland had been reconstructed by drawing each section 

 on blotting paper, cutting out and pasting together the individual 

 sections, and coating the whole model with a beeswax and 

 paraffin mixture, it was impossible to get an adequate idea of 

 the complete gland. The lobes were so complicated in some 

 planes of the section that it was not certain that no salivary 

 reservoir entered the question. As the work was completed, 

 however, it became evident that the structure in which the 

 flagellates were located was a three-lobed thoracic salivary gland, 

 with a single common exit. A diagram of the longitudinal 

 section through the opening of the three lobes is to be seen in 

 Fig. 3- 



FIG. 4. A portion of the efferent duct of the salivary gland of Oncopeltus. 



The cells of the duct are characteristic and interesting and 

 with the -secreting cells of the gland are so readily recognizable 

 that no difficulty arises in identifying them even in sections which 

 show but a tiny fragment of the salivary apparatus. 



The duct is lined with a single layer of cells the nuclei of which 

 are sometimes branched. A portion of the duct is represented 

 in Fig. 4. A similar detailed drawing of the cells of the wall of 

 the salivary gland is shown in Fig. 5. The glands are commonly 

 distended with fluid. This escapes gradually, as required, 

 through the efferent duct. 



With the recognition of this organ as a thoracic salivary gland 



