Abstract
An ovary-like organ was observed on the lower side of the right preopercle of a male puffer Takifugu rubripes (Temminck et Schlegel), which had a body weight ca 6kg and a testis weight ca 600g. This puffer was caught in Ainoshima Island, Kitakyushu City, Japan, on January 24, 1982. The organ was oval in shape, and the size of a ping-pong ball (ca 20g), and was separated by thin membranes into more than 4 parts. Two groups of eggs were observed: large-sized (0.75-0.95mm; mean 0.80mm in diameter) and small-sized (0.45-0.55mm; 0.50mm). The latter were far more numerous than the former. Histologically, yolk vesicles or yolk globules in all the eggs formed a large mass and were in a state of liquefaction. No clear nucleuses were observed in almost all the follicle and ovarian stomal cells and the eggs, indicating deterioration. The organ and surrounding muscles were found to be non-toxic (less than 5 MU/g). The extra-regional ovary-like organ from T. rubripes, and migration of primordial germ cells to the intermuscular connective tissues of the head region in teleost were recorded for the first time.
