MAMMALS. 165 



been the involuntary means of leading to the final 

 extinction ; while occasionally, as in the case of the great 

 auk, a catastrophe of nature has accelerated the climax. 

 In other instances, it would seem that a species has been 

 gradually dying out from unknown natural causes, in the 

 manner which appears to be natural to all forms of animal 

 life, where species and genera, like individuals, have but a 

 certain allotted spa,n of existence. 



In the present chapter we propose to notice the chief 

 animals, exclusive of invertebrates, which are known to 

 have been exterminated, or are just verging on extinction, 

 within the historic period ; but before doing so we may 

 briefly allude to a few others which urgently require pro- 

 tection, unless they are to share the same fate. Foremost 

 among these are the African elephant and the so-called 

 white, or square-mouthed, rhinoceros of the same country. 

 Till within a short time ago there were, indeed, strong 

 grounds for believing that the latter magnificent animal, 

 which at present is represented only by a few skulls and 

 horns in English collections, had already disappeared ; but 

 we are rejoiced to hear that a few individuals still linger 

 on in a remote corner of Eastern Africa, where it is to be 

 hoped they will receive immediate and adequate protection. 

 The walrus of the polar regions is another animal whose 

 numbers have been woef ally diminished of late years, and 

 which likewise stands in urgent need of protective legis- 

 lation, while a similar remark will apply to several species, 

 or local races, of seals. In countries like New Zealand, 

 where there were originally no native carnivorous animals, 

 many of the indigenous creatures now stand in great 

 jeopardy by the introduction of the latter, and it is only 

 too likely that the flightless kiwis of those islands will 

 eventually be exterminated by half-wild cats and dogs. 

 The curious tuatera lizard of the same country is also 

 likely to be killed oft' by pigs.* In the Samoan Islands a 

 similar fate long threatened the tooth-billed pigeon 

 (Didunculus) the nearest living ally of the dodo but 

 the impending destruction was fortunately averted by the 



* See page 161. 



