54 MAMMALIA 



within enclosures. They were therefore allowed to roam freely over 

 the open country, and were only mustered at rare intervals for shearing, 

 tailing the lambs, etc. It was inevitable, therefore, that numbers 

 escaped the musterers, especially on high and inaccessible country, 

 and that thus wild sheep became very common, especially in the 

 mountain districts of the South Island. 



Twenty or thirty years ago when the minds of naturalists were 

 saturated with Darwinian views, it was somewhat confidently antici- 

 pated that isolation would lead to the rapid development of new 

 varieties and species, and that such changes might well be looked 

 for in New Zealand. At the meeting of the Australasian Association 

 in Christchurch in 1891, 1 read a paper " on some Aspects of Acclima- 

 tisation in New Zealand " from which I take the following extract : 



In the district of Strath-Taieri, in Otago, some years ago, certain sheep 

 on one of the runs probably the progeny of a single ram were found 

 to be evidently short-winded. Apparently the action of the heart was 

 defective, for, when these sheep were driven, they would run with the rest 

 of the flock for a short distance, and then lie down panting. The result of 

 this peculiar affection was that, at nearly every mustering, these short- 

 winded sheep used to be left behind, being unable to be driven with the 

 rest. Sometimes they were brought on more slowly afterwards; but, if it 

 happened to be shearing-time, they were simply caught and shorn where 

 they lay. As a result of this peculiar condition, a form of artificial selection 

 was set up, the vigorous, active sheep being constantly drafted away for 

 sale, etc., while this defective strain increased with great rapidity through- 

 out the district; for, whenever the mobs were mustered for the market, 

 shearing, or drafting, these "cranky" sheep (as they came to be called) 

 were left behind. This defective character appeared in every succeeding 

 generation, and seemed to increase in force, reminding one of the Ancon 

 sheep referred to by Darwin. At first, of course, the character was not 

 recognized as hereditary; but, as the numbers of this "cranky" breed 

 increased to a very serious extent and spread over the district, it came at 

 last to be recognized as a local variety. When the runs on which these 

 sheep were abundant were cut up and sold, or re-leased in smaller areas, 

 the purchasers found it necessary, for the protection of their own interests, 

 to exterminate the variety, of which hundreds were found straggling over 

 the country. This was easily and effectually done in the following manner. 

 As soon as a sheep was observed it was pursued ; but, after running for a 

 couple of hundred yards at a great rate of speed, it would drop down panting 

 behind a big stone or other shelter, and seemed incapable for a time of 

 rising and renewing its flight. It was immediately destroyed ; and, in this 

 manner a useless but, to the naturalist, a very interesting variety was 

 eliminated. 



Wild sheep are still abundant in some of the wilder parts of the 

 country, and are especially numerous in the high limestone country 

 of Marlborough. Mr Aston says: 



