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Abstract The development of the starfish Asterina (= Patiria) pectinifera (Muller et Troschel) from fertilization to metamorphosis took 27–28 days at 22°C and a salinity of 33–33.4‰. The embryonic development was completed by the release of swimming ciliary blastula from egg envelopes 13 h after fertilization. The larvae passed into the stage of gastrula and reached the stage of dipleurula in 35 h and the stage of bipinnaria in 3.5 days. At the stage of brachiolaria, by the 12th day of development, two lateral brachioles and one medioventral brachiole with papillae developed in the larvae. The attachment disk and the primordia of five radial canals of the juvenile starfish became visible by the 15th and 18th days, respectively. By the 24th–25th day, a differentiated primordium of a juvenile starfish had developed in the brachiolaria. The size of the larvae prior to settlement was 1765.4 ± 51.5 µm. Metamorphosis was completed one day after settlement. [ABSTRACT FROM AUTHOR]

The effects of seawater temperature (12, 16, 20, 22, and 25°C) and salinity (of 8 to 34‰) in different combinations on the larvae of the rhizocephalan Peltogaster reticulatus (Crustacea: Cirripedia), a parasite of the hermit crab Pagurus proximus, were examined. The development of P. reticulatus is comprised of five naupliar stages and one cypris stage. Nauplii have a specific structure, the flotation collar encircling the dorsal side of the larval body. Larvae lack the pigmented nauplius eye, and they show no positive phototaxis. Successful naupliar development occurred in temperature and salinity ranges of 16–25°C and 20 to 34‰, respectively; but all nauplii died at 12°C and 16‰. The duration of each naupliar stage increased under lowering of the seawater temperature. At 22–25°C and 26–28‰, the entire development cycle was completed in 72–80 h; and at 16°C and 20‰ it lasted 153 h. The cypris larvae showed a greater resistance to decreased salinity in comparison with the nauplii. At temperatures of 16–25°C and salinities of 14 to 34‰, the lifespan of cyprids was 6 to 12 days, and it decreased at increasing temperature. [ABSTRACT FROM AUTHOR]