Gross anatomical and microscopic observations on the orbit and its contents in Notomys alexis

Abstract

The gross anatomical arrangement of the orbit and its contents in N. alexis are described, with observations of these structures with the light microscope and of the retina with the transmission and scanning electron microscope. The eye is large compared with that of other rodents, and, in view of the rod outer segment length (43 ¼m), may afford sensitive nocturnal vision. It is unlikely that the animal has stereoscopic vision. Behavioural and microscopic evidence suggests that N. alexis has considerable processing of the visual signal at a retinal level, which may facilitate its rapid response to any sudden movement within the wide area of its visual field.