isophotes to NW and SE from the main body. Outside the main body the arm does not end but goes to NW from its edge as far as $\approx$40" (18 kpc). In Fig.2 one can see faint ($V\,=\,$18.7) galaxy projected on the NE edge of NGC 3808B. We think this galaxy is background one seen here by chance. However, it may be gravitationally bound with NGC 3808A,B but because of its non-distorted structure it is located sufficiently far from the pair and does not participate in strong gravitational interaction between A and B galaxies.

### Host galaxy

Observed colour indexes of NGC 3808B listed in Table 2 correspond to the normal Sab-Sb galaxy. After reducing for redshift and inclination made in accordance with RC3 recommendations the colour indexes ($B-V\approx$+0.5, $V-R\approx$+0.4) correspond to Sc-Scd galaxy (Buta et al. 1994, Buta & Williams 1995).

The photometric profile along the major axis ($\rm P.A.=55^{o}$) is shown in Fig.3a. As one can see, the surface brightness distribution is nearly exponential (note the contribution of star and faint galaxy in SW and NE parts of the profile correspondingly at $\rm r\geq20"$). Representing the profile by exponential law we find that the parameters of the brightness 