The Hubble Space Telescope Extragalactic Distance Scale Key Project. XXIII. The discovery of Cepheids in NGC 3319

The distance to NGC 3319 has been determined from Cepheid variable stars as part of the Hubble Space Telescope Key Project on the Extragalactic Distan ce Scale. Thirteen and four epochs of observations, using filters F555W (V) and F814W (I), respectively, were made with the Wide Field Planetary Camer a 2. Thirty-three Cepheid variables between periods of 8 and 47 days were d iscovered. Adopting a Large Magellanic Cloud distance modulus of 18.50 +/- 0.10 mag and extinction of E(V-I) = 0.13 mag, a true reddening-corrected di stance modulus (based on an analysis employing the ALLFRAME software packag e) of 30.78 +/- 0.14 (random) +/-0.10 (systematic) mag and the extinction o f EV-I) = 0.06 mag were determined for NGC 3319. This galaxy is the last ga laxy observed for the HST H-o Key Project.