NOTES. 569 



suppose that the prairies were once covered with trees, which have been 

 gradually destroyed by fires. Others suggest that the earth on the treeless 

 plains contains too much salt or too little organic matter to be favourable to 

 the growth of trees. No one, so far as I know, has suggested a climatic ex- 

 planation of the circumstances. Want of drainage may produce a swamp, 

 and the deficiency of rainfall may cause a desert, both conditions being 

 fatal to forest growth, but no one can mistake either of these treeless 

 districts for a steppe or a prairie.'' See also for general description of 

 steppe vegetation Kerner's Plant Life and Wiesner's Biologic der Pflanzen. 



Note 17, p. Ql.—The Quagga. 



The true quagga (Equiis quagga), intermediate between zebras and 

 asses, is no longer known to exist, though it was described by Sir Corn- 

 ■wallis Harris in 1839 as occurring in immense herds. The name quagga 

 is given by the Boers to Burchell's zebra {Equus hurohelli). 



The same sad fact of approaching extermination must be noted in regard 

 to not a few noble animals, e.g. rhinoceros, hippopotamus, and giraffe. 



Selous writes in 1893 : " To the best of my belief, the great white or 

 square-mouthed rhinoceros {Rhinoceros simus), the largest of modern ter- 

 restrial mammals after the elephant, will, in the course of the next few 

 years, become absolutely extinct. Yet, twenty years ago, it was a common 

 animal over an enormous extent of country in Central South Africa. 



" Never again will the traveller be able to stand upon his wagon-box, 

 and, like Burchell, Andrew Smith, Cornwallis Harris, and Gordon Gum- 

 ming, scan plains literally darkened by thousands upon thousands of wilde- 

 beests, quaggas, Burchell's zebras, blesboks, hartebeests, and spring-boks." 



Note 18, p. °n.—The Buffalo. 



The American bison or buffalo {Bos americanus) is now practically 

 exterminated. 



Two sentences from An Introduction to the Study of Mammals, by Sir 

 W. H. Flower and Mr. R. Lydekker (London, 1891), put the case in a 

 nutshell. 



"The multitudes in which the American bison formerly existed are 

 almost incredible ; the prairies being absolutely black with them as far as 

 the eye could reach, the numbers in the herds being reckoned by millions." 



With the completion of the Kansas Branch of the Pacific Eailway in 

 1871, the extraordinarily careless and ruthless slaughter began. In less 

 than ten years bison-shooting ceased to be profitable. 



And now, " A herd of some two hundred wild individuals derived from 

 the northern herd is preserved in the Yellowstone National Park ; and 

 it is believed that some five hundred of the race, known as Wood-Bison, 

 exist in British territory ; hut with these exceptions this magnificent species 

 is exterminated ". 



A vivid account of the bufi'alo's habits and of its rapid tragic extermina- 



