[Microscopic research on arachnoid villi in various mammals]

The sagittal sinus in the man, dog, cat and rabbit was studied; we have noted remarkable histological differences within the zoological succession in the system of discharge of the cerebrospinal fluid in the venous system. The differences, probably, are chargeable to the different metabolic encephalic exigences which in the man are exalted and which justify the presence of the more complicated structures.