Abstract:
The infra-orbital cutaneous sinus produces a black secretion which is the combined secretion of melanaceous, branched, alveolar, sebaceous and enlarged, coiled apocrine glands. The micromorphology of these glands is described with special emphasis on the sebaceous glands and melanin transfer. The secretion, which may be used for unintentional territorial demarcation, is possibly produced as small black granules and is most likely important for short range communication.