Abstract
Cyclichthys orbicularis (Diodontidae, Tetraodontiformes) were spawned in captivity, the larvae being reared for more than 60 days, in the Shimonoseki Marine Science Museum Aquarium. Isolated epipelagic eggs, 2.2 mm in mean diameter, hatched two days after spawning. Hatched larvae were 3.5 mm in total length, the head and trunk being covered by a "vesicular dermal sac". Fin rays were completed in 17 days after hatching at 7.6 mm TL, some rudimentary spines appearing on the dorsum. Spines had become unmovable in 39 days after hatching at 20.8 mm TL. Growth rates from hatching to 8 days and thereafter from 9 days were different, growth regression equations between TL (y) and days after hatching (x) being y = 0.052x + 3.518 and y = 0.295x + 2.046, respectively.
