What is a peculiar galaxy?

Following the recent surge of interest in peculiar galaxies at high redshiftswe consider the definition, or lack thereof, of morphological peculiarities ona sample of local universe galaxies. Studying the morphology of local universegalaxies is also of interest in trying to understand galaxy dynamics andquantifying the relations between morphology and environment. We useclassifications given by five experts for a sample of 827 APM galaxies and findthat there is little agreement between them on what qualifies as a peculiargalaxy. We attempt several objective approaches : matching galaxy images to``templates''; examinig the 180-degree Asymmetry against Light Concentration(following Abraham et al. 1995); and exploring angle-dependent asymmetrymeasures. While none of the quantities we use results in a clean distinctionbetween normal and peculiar galaxies, there is a rough correlation between someparameters and image peculiarity. However, the mixing between the two classesis significant. We conclude that the class of peculiar galaxies is not totallydistinct from the class of normal galaxies, and that what we are seeing isreally a sequence. It is therefore more useful to consider distributionfunctions of morphological parameters. The current and possibly other, moreaccurate parametrisations require better data, which is becoming availablethrough CCD imaging.Comment: 6 pages, latex, 12 figures. Postscript also available from ftp://ftp.ast.cam.ac.uk/pub/hn/pecs . Submitted to Mon. Not. R. Astr. Soc