Figure 1.

Anatomical comparison of C. briggsae and C. elegans. (a) The C. briggsae hermaphrodite. (b, c)Vulval invagination in L4 larvae of (b) C. elegans and (c) C. briggsae. The vulval morphology of C. briggsae is almost indistinguishable from that of C. elegans; minor differences include a slightly thicker vulval-uterine connection (utse) in C. briggsae.