EFFECT OF OSMOLALITY ON THE MOTILITY OF SPERM FROM THE LAMPREY, LAMPETRA-JAPONICA

Lamprey (Lampetra japonica) sperm were immotile not only in the seminal plasma but when immersed in an isotonic lamprey Ringer solution. Sperm were also found to be immotile when the semen was diluted with NaCl, KCl, or glucose solution isotonic to the Ringer solution. Sperm became motile, however, after dilution of semen with an hypotonic solution. These results suggest that motility of the lamprey sperm is probably suppressed by the osmolality of the seminal plasma and is initiated by a decrease in osmolality upon dilution into the spawning media (river water).