Fig. 1

Nomarski images of C. elegans vulva at different L4 sub-stages (L4.0 – L4.9). Each sub-stage is distinguished from another by the morphological appearance of the vulva (Table 1). All images in this figure were taken in the focal plane corresponding to the midline of the worm. L4.0: arrows point to undivided cells. L4.1: arrow points to the vulval lumen. L4.2: arrow points to the "kink" between vulC and vulD cells. vulCs are out of the plane of focus. L4.3: the anchor cell and vulF cells are labeled. L4.4: the utse cell separating the vulva lumen from the uterine lumen is indicated by the white arrow. Black arrows point to "fingers" which form on sides of the vulva. L4.5: the concave curve between vulD and vulB2 is shown (black arc). L4.6: ventrally oriented "fingers" are indicated by black arrows. L4.7: the opening between vulF cells are starting to narrow. L4.8, L4.9: the vulval lumen (black arrow) collapses during these stages