ON THE ENTRANCE OF THE CAROTID ARTERY INTO THE CRANIAL CAVITY IN STENOPS GRACILIS AND OTOLICNUS CRASSICAUDATUS

Abstract

The arterial blood supply of the mammalian brain is protected in several ways, one of which is the mode of entrance of the artery into the cranial cavity. Most mammals rely upon an intra-cranial rete mirabile, or upon a bony canal enclosing the artery, or upon a combination of both. There are, however, 2 species of lemurs, Loris gracilis and Galagos senegalensis, which are equipped with an extracranial rete mirabile of the internal carotid. In these animals the entrance of the artery into the skull is accordingly modified and reduced from a canal to a foramen.