TTJBIFEX. 325 



all his figures of the chloragogen cells of Enchytrasus. 

 Mcintosh appears to have made efforts to demonstrate 

 the presence of a nucleus in the fresh, unstained chlora- 

 gogen cells of Tubifex, but owing, as he says, to the large 

 number of granules always present in the cell, he was not 

 able to do this. It certainly does need considerable care 

 in observation in order to see the nucleus, but it is 

 comparatively easy to do so if the cells are floated on to a 

 large quantity of water on a slide and a cover-glass put 

 on. The cells then roll about in the water, and during 

 their movements it is often possible to see the nucleus. 

 Mcintosh also states that even after careful examination 

 of transverse and longitudinal sections of the worm he 

 arrived at the same result. I find, however, that 

 in any section of the intestinal part of the worm, which 

 has been appropriately stained, viz., with borax-carmine, 

 the nuclei can be very plainly seen, as they are large and 

 each has a distinct nucleolus (PL III, fig. 13). 



The true shape of the cells is better seen in sections 

 than by examining them in the fresh condition. In 

 sections they are seen to be truly pear-shaped, the 

 broader end lying freely in the body cavity. In such 

 preparations the nucleus, which is oval in shape, is 

 usually situated in the narrower part of the cell. It is 

 quite useful to make permanent smears of these cells and 

 stain them on the slide. A stain which differentiates the 

 nucleus particularly well is Brazil in. In these smears 

 the granules stain very slightly : not nearly so heavily 

 as does the nucleus (PL III, fig. 15). 



Rice (1902) has published a paper on the chloragogen 

 cells of Lumbricus herculeus, and he enters in some detail 

 into their origin, growth and structure, and gives some 

 suggestions as to their function. It is evident from Ins 

 descriptions that their growth and structure are very 



