"In many GFP-positive ceh-6
mutant animals no excretory cell could be discerned in differential interference contrast (DIC), and no excretory cell with its canals could be seen using the vha-1
::gfp reporter gene, although GFP is present in many vesicular type structures throughout the animal (data not shown). In some cases, the excretory cell could be clearly identified in DIC, and abnormally short and enlarged excretory canals were revealed with vha-1
::gfp (Fig. 5J-M)."