Histological sections of gonads of Chlorurus microrhinos from Fiji. (A) ovary of immature female (36.3 cm LF) containing primary-growth (I) and cortical vesicle (II) oocytes, plus a conspicuous lumen (L); (B) ovary of mature female (37.1 cm LF) containing a mixture of oocyte stages including final maturation (IV); (C) testis from an immature male (38.0 cm LF) containing no tailed spermatozoa, but with a conspicuous lumen (L); (D) testis of a mature male (38.7 cm LF) with tailed spermatozoa (S); scale bars = 100 μm (A and B) or 50 μm (C and D).