Fig. 5
From: Plasticity and regeneration of gonads in the annelid Pristina leidyi
Post-embryonic contexts in which gonad development occurs in clitellate annelids. a In starved animals that have lost detectable gonads, gonads are reestablished upon feeding in the original gonadal segments. b During morphallactic regeneration, gonads develop in previously non-gonadal segments. c During paratomic fission, gonads arise in newly formed segments that develop within the fission zone; note that gonads (ovaries) are shown attached to the poster-most new septum (as previously suggested [32]), extending from new tissue (gray) into previously existing tissue. d During epimorphic regeneration following amputation (or fragmentation), gonads develop in newly formed segments; shown here is a scenario in which gonads form on the two posterior-most new septa made during regeneration, as seen during regeneration in a number of clitellate annelids. As in panel c, new tissue is indicated by gray shading