NOVEMBEE 20, 1896.] 



SCIENCE. 



745 



■which can produce such marked and 

 unfavorable results in a herd protected as 

 carefully as that in the Bieloviejsha forest, 

 The factors which have brought about this 

 decrease may be divided into two principal 

 categories : first, tliose wholly external ; and 

 second, those proceeding from the animals 

 themselves. Under the first head are dis- 

 cussed : hunting, poaching, taking of live 

 specimens for zoological gardens, ravages of 

 beasts of prey and of various diseases, and 

 finally possible deaths from shortage of food 

 supply. As all these factors taken to- 

 gether are shown to be insufficient to 

 account for the present condition of the 

 herd, the true reason must be sought in the 

 animals themselves. As long ago as 1830 

 Jarocki noticed that the bison cows as a 

 rule calve only once in three years, and 

 this observation has been repeatedly veri- 

 fied. The question at once arises whether 

 this low grade of fertility is natural or 

 otherwise. A careful study of the breeding 

 habits of the bison in the Bieloviejsha forest 

 and elsewhere leaves no room for doubt 

 that the present slow rate of reproduction 

 is an abnormal condition, and that to it is 

 due the rapid approach of the extinction 

 which is the certain fate of the herd under 

 consideration. This diminished fertility 

 the author regards as a stigma of degenera- 

 tion caused by in-breeding. Associated 

 with it are other stigmata, such as fatty 

 degeneration of various organs and abnor- 

 mal condition in parts of the skeleton. 

 Many of the bison cows are known to be 

 wholly unable to care for their calves 

 through lack of milk. The process of de- 

 generation has progressed so far that the 

 more degenerate animals may be recognized 

 by their paler color, weaker horns and 

 thinner fur. Of eleven captured by Strahl- 

 born in 1858, four were of the pallid, thin- 

 haired, degenerate type. Another indica- 

 tion of the degenerate condition of the 

 Bieloviejsha herd is seen in the great 



excess of bulls, which probably outnumber 

 the cows two to one. This is doubtless a 

 result of in-breeding, for Diising (Jena 

 Zeitschr. fiir N"aturwiss, Bd. XVII., p. 827, 

 1884) has shown that close in-breeding, like 

 a reduced condition of nutrition, is favor- 

 able to the production of an excess of males. 

 Thus the total extinction of the Bieloviejsha 

 bison is certain to occur, and that probably 

 in the near future. Such a fate the author 

 points out overtook the last herd of Bos 

 primigenius in Poland during the early part 

 of the seventeenth century, notwithstanding 

 the most careful protection. 



In conclusion, the author considers that 

 his studies of the history of the Bieloviejsha 

 bison leave scarcely room for doubt that in- 

 breeding is the cause of the final extinction 

 of most large mammals. In-breeding must 

 begin and lead gradually but certainly to 

 the extinction of a species when it, through 

 any cause, has become so reduced in num- 

 bers as to be separated into isolated colonies. 



If Biichner's conclusion is correct — and 

 few will doubt that it is — we may look for 

 the speedy extinction of the American bison, 

 whatever means may be taken for the 

 protection of the few remaining individ- 

 uals, while the danger attending any con- 

 siderable reduction in the size of the Pribi- 

 lof Island seal colonies, with the expecta- 

 tion that they will regain their former size 

 under subsequent strict protection, becomes 

 fully apparent. 



Gerrit S. Miller, Jr. 



DENTITION OF LEMURS AND THE SYSTE- 

 MATIC POSITION OF TABSIU8. 



In a recent number of Science appeared 

 an abstract by Prof. A. A. W. Hubrecht, 

 of his contribution to Gegenbaur's Festschrift, 

 giving his conclusions upon the relations of 

 Lemurs and monkeys, especially upon the 

 position of Tarsius among the Anthropoidea. 

 It is interesting to find, in the same col- 

 lection of memoirs, a contribution from 



