In July 1938 I succeeded in rearing the hydroid of Eutima gracilis (Forbes and Goodsir) (also known as Saphenia gracilis) from adult medusae which liberated their eggs and sperm in finger-bowls of sea water. These hydroids were only in the primary polyp stage, and I withheld publication hoping to repeat the work later and perhaps rear the hydroid to a more advanced stage. As it is unlikely that I may now have the opportunity of doing this it seems worth while to publish a short account with figures of the polyp.