Within the area above described, Janssen measured and described fifty-one Hunebeds still existing, and they were probably at one time much more numerous, as he regrets the loss of four which he remembers in his youth; and several others have been very much ruined in very recent times. This, fortunately, is not likely to happen again, as, with a liberality and intelligence not shown by any other government in Europe, the Dutch have purchased the Hunebeds and the ground on which they stand, with a right of way to the nearest road, so that, so far as possible, they will be protected from future depredations. Of these fifty-one monuments only one is a dolmen, in the sense in which we usually understand it, meaning thereby a single cap stone, supported by three, or, as in this instance, by four uprights. This one is near Exlo, and is one of the few that formed a chamber in a tumulus. A few have three cap stones, and from that number they range up to ten or twelve, with at least double that number of supports. They are all, in fact, of the class which the French call "allées couvertes," or "grottes des fées;" Calliagh Birra's house (woodcut No. 80) and the dolmens at Glen Columbkill are of the same class. But the Drenthe dolmens have one peculiarity not found either in France or Ireland: that they are all closed at both ends, and the entrance, where there is one, is always on the longer side. In this respect they more resemble the Scandinavian examples, such as the tomb at Axevalla (woodcut No. 116), or that at Uby (woodcut No. 114). [Illustration: 120. Plan of Hunebed near Emmen.]