300 NATURAL SCIENCE [November 



such a Sirenian as the existing manatee in but the smallest par- 

 ticulars. Some of its teeth seem to have been replaced by vertical 

 successors. The vertebrae exhibit distinct traces of terminal epi- 

 physes in young animals. The hind limb is represented not only 

 by the rudimentary pelvis, but also by a trace of the femur. 

 Otherwise, its skeletal parts are almost identical with those of its 

 surviving relative. Since the Sirenians came into existence, indeed, 

 very little change has taken place among them. 



The Beaver in Norway 



The beaver, which was once so common throughout northern 

 Europe, still survives in Norway, and several notices of its occur- 

 rence in that country have been published in recent years. These 

 notices, however, are more or less limited in their scope, and Prof. K, 

 Collett, the eminent zoologist of Christiania, has lately done good 

 service in investigating the whole subject with thoroughness. His 

 results are published, with twelve beautiful photographs of the 

 modern beaver-haunts, in the first article of the Bergens Miiseums 

 Aarbog for 1897. 



Trade in beaver skins was carried on in Norway in the Middle 

 Ages, and the former wide distribution of the animal in the country 

 is indicated by reference to it in many place-names. Now, how- 

 ever, its range is much restricted, and unless the laws for its pre- 

 servation are rigidly enforced it will soon become quite extinct. 

 It is chiefly confined to the Stifts of Christiania and Christiansand, 

 and the largest colony is at present located in the middle and 

 southern parts of the river Nisser (or Nid) in Nedenaes Amt. The 

 banks of this river are for the most part covered with forests of 

 Pinus sylvestris, and wherever these are interrupted by trees with 

 deciduous leaves the beaver is to be found. Its chief food is the 

 fresh bark of the last-mentioned trees, especially of Populus tremula ' r 

 and for winter use small branches with the bark on are submerged in 

 the water in front of the habitations. Bark that has been gnawed 

 off is not collected for winter provender. Most trees are felled 

 quite close to the water, and they are rarely brought from a distance 

 of more than 300 metres. 



Immediately after the break-up of the ice in spring, the beaver 

 commences to search for food, and traces of it are sometimes seen in 

 the snow. Work on the lodge or habitation is mainly done in the 

 autumn, and almost exclusively at night. When the animal is seen 

 in the daytime, it is as a rule only swimming in the water without 

 any set task on hand. 



The trees cut down by the beaver do not fall in any one definite 

 direction, but lie pointing in every way. The current of the river 

 is used for transport purposes whenever possible ; but most of the 



