Abstract
The structure of the urogenital papilla of the oviparous fish, Aulichthys japonicus, was observed and the function of the organ was discussed.The epithelium, corium and layer striated muscle place continuously from the peripheral to central portion of the papilla.Although the origin of the papilla in this species appears to be the same as that of ovoviviparous rockfishes, Sebastes and Sebastiscus, the internal structure of the former shows marked differences from that of rockfishes.
