1902 The Faiuia of Nezv Zealand 45 



within their original faunal limits ; and (6) causes assisting 

 to diffuse them from those original faunal limits. The first 

 class, or the barriers to the spread of species, are chiefly 

 to be found in ocean and mountain barriers, and in the 

 influence of climate. The second class, or the means of 

 dispersal of species, are such factors as the seasonal changes 

 producing migrations, ocean currents, trade winds, great 

 rivers, and, in past times, geological changes. As the result 

 of such influences as just mentioned, the fauna of New 

 Zealand is peculiar to itself, and the only point in this brief 

 note is to draw the attention of the student of animals to 

 those peculiarities. 



First as regards Mammals. These are conspicuous by 

 their absence, being represented by a solitary rat ; and it is 

 even doubted whether this is a truly indigenous species, or a 

 descendant of some taken to the colony in the ships of the 

 earliest European visitors. 



Taking the Birds next in order, a very different state of 

 affairs is found to obtain. There are no less than sixty- 

 nine families of land birds, fifty-eight of which are not found 

 elsewhere. These include about twenty species of the so- 

 called wingless birds, " surviving relatives of that feathered 

 giraffe, the extinct Moa " (Aflalo). The raptorial birds are 

 not prominent, probably because there are no small mam- 

 mals to provide food. Very curious is the fact that the 

 strong flying birds of Australia do not cross to New Zealand, 

 more than half the birds of that continent being found no- 

 where else. True there is a matter of some twelve hundred 

 miles of water between the two places, but one would have 

 expected a much larger interchanging of birds than actually 

 occurs. Thus one of the Australian swifts, which flies at a 

 great altitude, and which has been credited with being able 

 to perform the feat of crossing Bass' Straits, a distance of a 

 hundred miles, in an hour, nevertheless never is known to 

 visit New Zealand. 



Coming now to the Reptiles, another remarkable feature 

 of the fauna is to be noted, namely, the entire absence of 

 serpents, at any rate as far as the species which dwell on 

 the land are concerned. Australia, on the other hand, has 

 more than one hundred varieties. This immunity from 



