G. NATURAL HISTORY AND ZOOLOGY. 339 



whale-fishery, this book occupies the first rank in the litera- 

 ture of the subject. It will doubtless have a large circulation 

 among the whalemen of Cape Cod and New England gener- 

 ally, since by a reference to it they can renew their experi- 

 ences, and fight over again their early battles. 



DECREASE IN THE EUROPEAN BISON. 



It is well known that the living representatives, in Europe, 

 of the European bison, which is closely allied to, if not iden- 

 tical with, the American bunalo, consist at present of a single 

 herd in Lithuania, the property of the Emperor of Russia. 

 Recent reports indicate a gradual decrease in their numbers, 

 with a probability of eventual extermination. It is many 

 years since the number exceeded 1000, and in 1858 it was but 

 559; in 1861,541; and in 1872, 528. 3 (7, May 25, 1874,420. 



EGGS OF THE SILTJRID^E. 



It is an interesting fact in the economy of certain fishes, 

 especially of those belonging to the family of the Siluridae, 

 that the mouth constitutes the nest for hatching the eggs, 

 these to the very limited number of from five to twenty be- 

 ing kept in this cavity, usually that of the male, until they 

 are hatched. They are probably caught up after exclusion 

 and fertilization, and retained. Some of these eggs are half 

 an inch in diameter. The fact of this peculiarity in the case 

 of the genus Arias and some of its allies in America has long 

 been known ; and Dr. Day announces the same condition in 

 certain Indian species of Arias and Osteogeniosus. 12 A, 

 February 5, 1874,272. 



DISCOVERY OP PUTORIUS NIGRIPES. 



Among the new animals described by Audubon and Bach- 

 man in their great work on North American quadrupeds 

 was a kind of weasel, named by them Putorius nigripes, or 

 black-footed ferret, of which a single specimen came into 

 their possession, constituting apparently a good species. 



In the thirty years that have elapsed since the announce- 

 ment of this discovery diligent search has been made for ad- 

 ditional specimens, but in vain ; and it was not until recent- 

 ly that a skin was sent to the Smithsonian Institution from 

 the North Platte by Mr. La Munyon, one of its correspond- 



