Figure 23 in Review of the genus Zygothuria Perrier, 1898 and the Atlantic group of species of the genus Mesothuria Ludwig, 1894 (Synallactidae: Holothuroidea) with description of the new species Mesothuria milleri sp. nov.

Figure 23. Gametogenesis. (A) oogenesis in Zygothuria lactea; (B) oogenesis in Mesothuria milleri sp. nov; (C) early spermatogenesis in Z. lactea; (D) advance spermatogenesis in M. milleri sp. nov. Ac, follicle cells; Pv, previtellogenic oocytes; V, vitellogenetic oocyte; W, ovary wall; Oo, ooplasma of vitellogenic oocyte; Nc, nucleus and N1, nucleolus of vitellogenic oocyte; Ph, phagocytosed oocyte; Tw, testis wall; Sp, spermatozoa; Sc, spermatocyte; Sg, spermatogonia; In, indentation of testis wall. Scale bars 100 µm. A is periodic acid Schiff and haemalum; (B–D) are haemalum and eosin.