[Morphological observations on the cranial and facial bones of the crab-eating monkey]

Forty seven skulls of the crab-eating monkey (Macaca fascicularis) were investigated for their morphological characteristics. Five of them were disintegrated into component bones by the use of the papain. Each cranial and facial bone of this species resembled that of the rhesus monkey (M. mulatta) in its general morphology. Some obvious differences, however, were noticed in the detailed structure of the skulls between these two species. The uncinate process of the ethmoid bone was found in the rhesus monkey but was not found in the crab-eating monkey. The intrajugular process of the temporal and occipital bones was present in the crab-eating monkey but absent in the rhesus monkey. The nasal process of the incisor bone was sutured with frontal bone in the rhesus monkey but was not sutured with that bone in the crab-eating monkey.