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 Some of its teeth seem to have been replaced by vertical 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 oceur- 
rence in that country have been published in recent years. These 
notices, however, are more or less limited in their scope, and Prof. R. 
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 Musewms 
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 ; 
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 
