THE EFFECT OF SALINITY UPON THE RATE OF EXCYSTMENT OF ARTEMIA

Abstract

1. The excystment of Artemia takes place in two principal stages: first, the quiescent nauplius emerges from the shell of the cyst within a membranous sac, and then later the nauplius hatches from the sac and swims actively about.2. The excystment of Artemia obtained from the margin of San Francisco Bay has been studied at 25° C. in diluted and concentrated sea water over a salinity range from zero (distilled water) to 225 per cent sea water (i.e., a solution in which the salt concentration is 225 per cent of the salt concentration of sea water. No salts precipitated out).3. The same percentage of embryos emerged from the shells in all of these salinities, including zero salinity (distilled water).4. In distilled water the emerged embryos are motionless and they do not hatch from the sac. Some swell and burst.5. In 12½ per cent sea water, 83 per cent of the emerged embryos hatch; in 25 per cent sea water 93 per cent hatch. In 50-225 per cent sea water 96-99 per cent hatch.6. In 12½-225 per cent sea water ...