1 Introduction

About 1/7 of the 240 known galaxies with radial velocities $V_{\rm LG} < 400$ km s^-1 are concentrated in a small area in the Canes Venatici (CVn) constellation [ $\alpha = 11^{\rm h} 30^{\rm m}$ to $13^{\rm h} 40^{\rm m}$, $\delta = +25\hbox{$^\circ$ }$ to $+55\hbox{$^\circ$ }$] which occupies only 1/50 of the sky. Therefore, the apparent overdensity of the number of galaxies seen in the CVn direction exceeds $\delta N/ \langle N\rangle \sim 7$. This scattered complex of nearby galaxies has been noted by many authors (Karachentsev 1966; de Vaucouleurs 1975; Vennik 1988). In the Nearby Galaxies Catalog (Tully 1988) the group is indicated by "14--7'' (CVn I) as a part of the more extended Coma-Sculptor cloud, containing the Local Group (LG) and also the M81, Cen A, and Sculptor galaxy groups. In contrast to the groups mentioned, the CVn I cloud is populated mostly by late-type galaxies of low luminosity.

At present the structure and kinematics of the CVn I complex are still poorly understood because of the lack of reliable data on the galaxy distances. Sandage & Tammann (1982) determined the distance to IC 4182 (4.70 Mpc) from the luminosity of Cepheids. Distance estimates from the luminosity of the brightest stars were derived for DDO 154 (Carignan & Beaulieu 1989), DDO 168 (Bresolin et al. 1993) and UGC 8508 (Karachentsev et al. 1994). Using this method, Georgiev et al. (1997), Makarova et al. (1997, 1998), Karachentsev & Drozdovsky (1998), and Sharina et al. (1999) determined distance moduli for 35 spiral and irregular galaxies in CVn I. The median distance to the cloud was found to be 4.3 Mpc, which is in good agreement with the single Cepheid distance estimate. However, considerable distance modulus errors ($\sim$0.5 mag) have hampered the study of structure and kinematics of the CVn I complex. That is why the CVn I objects were included in the program of our snapshot survey of nearby galaxies with the Hubble Space Telescope (Seitzer et al. 1999; Grebel et al. 2000), where galaxy distances are determined on the basis of a much more precise method, via the luminosity of red giant branch tip stars. In the framework of this study of galaxies in the Local Volume we earlier investigated the Centaurus A group (Karachentsev et al. 2002a) and the M81 group (Karachentsev et al. 2000, 2001, 2002b). The first distance measurements for five members of the Cloud based on the HST data have already been published (Karachentsev et al. 2002c). Here, we present new distances for 18 galaxies in the CVn I area.