Fig. 3. CiVH-positive cells in the tail region become germ cells. (A,B) An early tadpole larva. Eight CiVH-positive cells were localized to the distal region of the tail (arrowheads in B). CiVH signals were also detected in the trunk region (arrow). (C) A late tadpole-stage larva. CiVH signals in the trunk were remarkably reduced (arrow). (D) A larva during tail resorption. CiVH-positive cells were found in the tail (arrowhead), and the CiVH signals in the trunk were undetectable. (E) A stage 3a juvenile. CiVH-positive cells were among those in the tail debris (arrowhead). (F,F') A stage 3b juvenile. CiVH-positive cells (arrowheads) remained among the cells in the tail debris (outlined). (G,G') A stage 4 juvenile. CiVH-positive cells were aligned within the tail debris, which was almost completely resorbed (outlined). (H,H') A stage 5 juvenile. CiVH-positive cells (arrowheads) were aligned within the tube-like structure. (I,I') A stage 6 juvenile. CiVH-positive cells (arrowhead) changed position within the tube to form a drop-like cluster. (J,J') A stage 7 juvenile. The CiVH-positive cells (arrowheads) were entirely surrounded by somatic tissue. The number of CiVH-positive cells in the gonad increased.