P OP ULAR MIS CELL ANY. 



4 2 3 



Rodents, Fossil and Living. M. E. L. 



Trouessart, in attempting to explain the 

 geographical distribution of living and fos- 

 sil rodents from the point of view of the 

 doctrine of evolution, divides the living ro- 

 dents into four principal groups, or tribes : 

 the cosmopolitan rats and their allies, which 

 appear to find everywhere and under all cir- 

 cumstances conditions favorable to their ex- 

 istence and multiplication ; the sciuromorphs 

 (squirrels and marmots) and the lagomorphs 

 (hares), almost exclusively of the northern 

 hemisphere; and the hystricomorphs (por- 

 cupines, Guinea-pigs, and capybaras), which 

 are now confined to the southern hemi- 

 sphere. The study of the fossil rodents 

 shows that these four types were neither 

 as narrowly confined to particular regions 

 nor, except the hares, as clearly defined and 

 separated from each other as now. The 

 types of the southern hemisphere were rep- 

 resented during the Miocene epoch in the 

 north of both continents, and appear to 

 have been driven south by glacial cold. The 

 existing types of rodents first appear in the 

 Eocene epoch, and by the side of them mam- 

 mals with similar dentition, of which the 

 chiromys of Madagascar may be regarded as 

 the last survivor. Some of the mammals of 

 the secondary epoch present the character- 

 istic incisors of the rodents, with molars 

 indicating a carnivorous or at least a more 

 omnivorous nature than that of . the great 

 majority of the modern rodents. Similar 

 incisors are found in a number of insectiv- 

 orous animals, as, for example, among the 

 shrew-mice and several types of ungulates. 

 "We are thus led to conclude that this type 

 of the rodents played at the beginning of 

 the Tertiary period an important part in 

 the history of a number of orders which 

 have now become more specialized. 



Whales and their Habits. A correspond- 

 ent of " Land and Water," who accompanied 

 the Dundee whaling fleet to Davis Strait 

 and Lancaster Sound last summer, mentions 

 the change that has taken place in the geo- 

 graphical distribution of the Arctic whale. 

 A century or two ago this animal was found 

 everywhere north of the sixtieth degree of 

 latitude, and extended many degrees farther 

 south on the east coast of America. It 

 abounded on the northern shores of Europe 



and the coasts of Iceland and Greenland, 

 frequenting the islands of Jan Meyen ami 

 Spitzbergen in incredible numbers. Now 

 it has deserted Spitzbergen and the north 

 of Europe, it is becoming rare on the coasts 

 of Greenland, and seems to be retiring far- 

 ther into the unpenetrated recesses of the 

 Polar Sea. Whalemen are not agreed as to 

 whether the- animals are actually diminish- 

 ing in numbers. Some believe that they 

 are still as numerous as they were at the 

 beginning of the century ; others predict 

 that the time of their total extinction is 

 approaching. They are still sometimes seen 

 in enormous numbers. Whales exceeding 

 forty-seven and forty-eight feet in length 

 are caught every year. Captain Deuchars, 

 of the Dundee fleet, two years ago took a 

 whale sixty-five feet long, the " bone " of 

 which measured twelve feet ten inches, and 

 which gave twenty-four tons of pure oil. 

 The largest whale ever caught in Davis 

 Strait, in 1849, had a "bone" fourteen 

 feet long, and yielded twenty-seven tons of 

 oil. The destruction of " suckers," or baby 

 whales, which is considerable, may have 

 something to do with the present decadence 

 of the fishery. Whalemen think that no 

 animal should be killed whose "bone" is 

 not more than six feet long. Whales may 

 live to a very great, but no one knows to 

 how great, an age. Although dead ones are 

 often found floating on the water, none are 

 ever discovered that have died from natural 

 causes. Whales are monogamous, and are 

 much attached to their consorts. The cor- 

 respondent who furnishes these facts tells 

 of an animal which came back every day 

 for a fortnight through great peril from the 

 fleet to the place where its mate had been 

 taken, regularly going over the course fol- 

 lowed by her in her flight, looking for her. 

 The animals sleep on the surface of the 

 water, enjoy fine weather and sunshine, and 

 are often seen at play on bright days. When 

 they are together in large numbers, the 

 water becomes covered with an oily exuda- 

 tion from their bodies, which has a sickly 

 smell, and attracts flocks of " molly " pet- 

 rels. They can live only on the most mi- 

 nute marine animals, for, though a whale's 

 mouth " would hold a whale-boat, with all 

 its crew, its gullet would be choked by a 

 herring. When feeding, it swims through 



