EN
Skulls of 892 house mice of five species (Mus Linnaeus, 1758), collected from 136 localities across Europe and Morocco, were studied. The analysis revealed that variations in size affected most of the characters considered, indicating a reed to size-adjust- the data. M. domesticus was morphologically the most variable of all the European mice yet this variability was not consistent with the distribution of subspecies domesticus and brevirostris, The population from Albania was distinct within the M. domesticus samples, resembling M. musculus in overall size. In M. musculus, a W-E gradient of size was found in some variables, especially in females, and a sex dimorphism appeared also in populations from western parts of its range. Among 619 mice from 66 samples across the Czech and Slovak Republics and western Ukraine, but not from populations from western Bohemia, only M. musculus was substantiated. In spite of the fact that M. spicilegus and M. macedonicus are genetically and morphologically very close, as many as 9 variables (both untransformed and size-adjusted) proved to be different between the two species while M. spretus was found to be morphologically intermediate.