Using stained acryl latex-injected techniques, the arterial circle of the brain in Acomys cahirinus Desmarest was studied. Results revealed an important individual variability of investigated structure. Three morphological variants were found: (1) the lack of typical arterial circle--opened in front and the back side, (2) partial opened at the back side, (3) completely closed arterial circle. This finding is opposed to many species of mammals, including rodents, and especially laboratory mouse. In our point of view, it seems to be a specific character.