602 ZOOLOGY 



SECT. 



as most Insects, the large majority of Birds, and Bats. The 

 Flying Fishes, Flying Dragons (Draco), Flying Phalangers, Flying 

 Squirrels, and Flying Lemur (Galeopithecus) are semi-aerial. 



The majority of land animals live at or near the sea-level, and 

 as we ascend mountains the fauna undergoes a gradual impoverish- 

 ment as the snow-line is reached. The higher ranges of all great 

 mountains have a characteristic Alpine Fauna. In the European 

 Alps, the Chamois (Rupicapra), Alpine Hare (Lepus variabilis) 

 and Marmot (Arctomys marmot) may be specially mentioned ; in 

 the Himalayas, Yaks (Poephagus), Musk-deer (Moschus), Goats, and 

 Ibexes (Capra\ besides abundant Birds and Insects ; in the Andes, 

 the Condor (Sarcorhamphus) ; in the New Zealand Alps, the 

 rapacious Kea or Mountain Parrot (Nestor notabilis). 



3. GEOLOGICAL DISTRIBUTION 



In considering the distribution of animals in past time, we are 

 met at the outset with the difficulty that our knowledge of 

 the subject is and must always remain very imperfect and 

 fragmentary. With few exceptions, only calcined, silicified, or 

 strongly chitinized parts are preserved in the fossil state, so that 

 whole classes of animals are absolutely unknown in that condition, 

 and of the rest our whole information depends upon the more or 

 less imperfect skeleton. Moreover, it is only under very favour- 

 .able circumstances that even the hard parts are preserved; the 

 chances are usually in favour of the animal being devoured or 

 disintegrated before there is time for it to be silted over with mud 

 or sand. And lastly, many rocks have been so altered by the 

 internal heat of the earth as to destroy any organic remains they 

 may once have contained. Thus while paleontology furnishes us 

 with the only sure test of phylogenetic speculation, it is a test 

 which, more often than not, is incapable of application, owing to 

 the extreme imperfection of many parts of the geological record. 



It is in the oldest of the stratified rocks that this imperfection 

 is most severely felt. In the Laurentian period, forming the 

 base of the sedimentary series (see Vol. I., p. 7), no animal or 

 vegetable remains are known. In certain Canadian serpentine rocks 

 belonging to this period there is found a remarkable structure 

 which, under the microscope, bears a certain resemblance to the 

 supplementary skeleton, with its canal-system, of an immense Fora- 

 minifer. On the assumption that it was the fossilized remains of 

 a member of this order, it was called Eozoon canadense, but recent 

 researches seem to show conclusively that the supposed fossil is of 

 purely mineral origin. Radiolarians and Foraminifera have been 

 described from the Pre-Cambrian rocks of Brittany, but the 

 nature of the bodies in question has not yet been established 

 beyond dispute. 



