Fig. 5. Gonads in giant X. laevis tadpoles. (A) Left and right ovaries in the female giant, NF stage 54. The largest oocytes are at Dumont stage IV, the animal and vegetal hemispheres are differentiated, and yolk is present. (B) Cross-section through the testis of the male giant. The presence of sperm in the testis (arrowheads) shows that the gonads are mature; however, the tadpole's external morphology corresponds to NF stage 53. Scale bars, 1 mm (A); 50 µm (B).