About the existence and endings of nerve fibres in the Cebus apella monkey's upper lip.

In the present research, fibres and nerve endings of upper lip of the Cebus apella monkey have been studied. Upper lip of 8 Cebus apella were analysed. The pieces were prepared according to the technic of Castro's silver impregnation and submitted to serial sections 8 micra thick. Our results permit to conclude that the Cebus apella monkey's upper lip has a great number of free nerve endings, between connective and epithelial layers in the mucosa and in the skin. The aspects of nerve fibres and their free and organized endings, like Meissner's corpuscles, in the upper lip mucosa of the monkey, allow comparison of similarity with those of man. The nerve endings in the lip skin of the Cebus monkey are also abundant, characterizing the hair follicles and sebaceous glands innervation and the free nerve endings encountered in the connective tissue as well as in the sub-epithelial layer.