THE INTERSTELLAR-MEDIUM IN THE SEYFERT-GALAXY NGC-7172

We present aperture and surface photometry of the Seyfert galaxy NGC 7 172, which is a member of the compact group HCG 90, and has a prominen t equatorial dust lane. We use the observed colour excess in the dust lane, obtained from broad-band B and V images, to estimate the neutral hydrogen content as M(HI)(tot) = 2.6 x 10(8) M. and log(M(HI)/L(B)) = -1.8. We analyse the flux from NGC 7172 at various wavelengths and di scuss the properties of the interstellar medium in the galaxy. Based o n the results from surface photometry, and the properties of the inter stellar medium, we conclude that the morphology of NGC 7172 is of type S0-Sa.