OCR Text |
Show 162 ON BRAINS OF THE POTTO AND SLOW LORIS. [Jan. 19, dividing into the two very stout posterior cerebrals. The disproportion between these arteries is very marked; in the Potto they are of about the same size. The posterior communicating artery is much thicker than tlxe posterior cerebral from which it arises. It communicates, in the same way as in the Potto, with the carotid considerably behind the point where the latter divides into the middle and anterior cerebral arteries. Antex-iorly there is a stout anterior communicating .artery, from which arises the, at first, single anterior cerebral; two fused anterior cerebrals only join for a brief space in the centre of the cox-pus callosum, separating again almost immediately. Text-fig. 14. Base of brain of Lemur macaco. c, carotid. Other letters as in text-tig. 13. Lemur coronatus resembles L. macaco; for the two anterior cerebrals just before they disappear into the interhemispheral fissure become fused, and after a short space of union separate again. There is thus, as in L. macaco, a more or less prolonged union between the two anterior- cerebrals instead of a short bridge |