These pictures are a focal series through the terminal bulb of the pharynx. The worm is lying on its right side, with anterior towards the upper left, and ventral towards lower left. The first image is a superficial cut through the very leftmost edge of the pharynx.
Subsequent images go consecutively deeper, until the last goes through the very rightmost edge.
The focal plans aren't equally spaced. They were chosen so that all the nuclei in the terminal bulb would be clearly visible in at least one. Click on a cell for information about it. If you have image loading turned off, you'll need to load the images first. See below for a list of cells by type.