トミヨPungitius sinensis (GUICHENOT)の稜鱗の発達について

The formation of the scutes in ten-seined sticleback, Pungitius sinensis (GUICHENOT) does not arise until the fish grows to 20mm in total length. Their development starts from the side of caudal peduncle and runs toward the anterior region of the lateral side of the body. The scutes in their early developmental stage are quite similar to scale-like particles, so called by YOSHINO and HAMADA (1950) and KOBAYASI and KAMIYA (1961) etc. By adding scale material, main and lateral ridges, these structures are gradually transformed into the scutes with characteristics peculiar to this fish. The contour of the completed typical scutes with mucous tube, main and network lateral ridges is rhombic in those found in the region of caudal peduncle and square in the anterior portion of lateral line. But a few small scutes in the anterior most portion of lateral line fail to develop, and they remain permanently in the state of scale-like particles. This fact shows at a glance that we can conjecture the scutes are formed by the gradual transformation from the scale-like particles in this fish.