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

Lamprey (Lampetra japonica) sperm were immotile not only in the semina l plasma but when immersed in an isotonic lamprey Ringer solution. Spe rm were also found to be immotile when the semen was diluted with NaCl , KCl, or glucose solution isotonic to the Ringer solution. Sperm beca me 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 b y a decrease in osmolality upon dilution into the spawning media (rive r water).