Figure 2 in Position and development of oocytes in velvet worms shed light on the evolution of the ovary in Onychophora and Arthropoda

Figure 2. External organization of the three major types of ovaries and associated structures in Onychophora. Scanning electron micrographs, ventral view, anterior upmost. A, exogenous ovary of Peripatopsis balfouri (Peripatopsidae, South Africa). Arrowheads indicate 'grape-like', stalked oocytes projecting from the ovarian surface. B, pseudoendogenous ovary of Metaperipatus inae (Peripatopsidae, Chile). Note the absence of stalked oocytes on the ovarian surface, which consequently appears smooth. C, endogenous ovary of Epiperipatus biolleyi (Peripatidae, Costa Rica) with a smooth ovarian surface. Abbreviations: lg, suspensory ligament; od, oviduct; of, ovarian funnel; ov, ovary; rs, seminal receptacle.