A tumulus in the Guisseny commune (Finistère), excavated about two years ago, covered over a sepulchral crypt. At the southeastern extremity was picked up a badly baked hand-made earthenware vase with four handles. Beside the vase lay a skull, on which could be made out traces of oxidation, which had probably been caused by the wearing of a metal band, which has not been found. This skull bears on the right side a little oval hole with cicatrized edges about an inch long by two fifths of an inch broad. The discovery of a bronze dagger and two bronze plaques leaves no doubt as to the age of this tumulus. This example of trepanation is the only well authenticated one of which I know in Brittany. It is true one skull has been mentioned as found beneath the megalithic monument of Saint-Picoux de Quiberon (Morbihan), which is even said to bear marks of sawing and scraping made in attempting trepanation, but this fact has been very much questioned, and the date at which the trepanation was performed, if performed it were, is very doubtful.23 The proof we are seeking of the antiquity of the operation of trepanation is not therefore to be found here. On a plain amongst the hills of the right bank of the Seine, above Paris, rises a mound resembling a promontory which is known as the Guérin mound, and consists of a vast deposit of chalk which was excavated long ago. Successive operations have brought to light eight caves, most of which contained a number of human remains, which were unfortunately dispersed without having been scientifically examined. One alone, opened in 1874, contained numerous bones belonging to individuals of every age and of both sexes, with polished flints, fragments of pottery, and implements of stag-horn. Amongst these relics was found the skull of an old man showing a very curious example of trepanation. It was unfortunately broken by the workmen in the very moment of discovery, and could only be very insufficiently examined. Other examples, however, which could be properly authenticated, are not wanting from the banks of the Seine and Marne; two fragments of skull were found in the canton of Moret, one of which had been trepanned during the life of its owner, and the other after death. We must also mention the crania presented to the learned societies at the Sorbonne, one of which came from the plateau of Avrigny, near Mousseaux-lès-Bray (Seine-et-Marne). Side by side with the skeleton lay polished hatchets, scrapers, and arrow-heads, fragments of pottery blackened by smoke, and lastly a solitary bone of an ox, pierced with three holes at regular distances, which had probably been used as a flute. Of nine crania found in this excavation three were pierced, two after death and one during life, the edges of the last named bearing very evident traces of treatment.