. 
iwá i Zoölogy. 283 
among a crowd of other birds, apparently for no other reason than 
because of its shining white plumage, and*he asks, how has it been 
possible for the twə white species.of South American heron to escape 
their enemies and continue to exist ? 
Mammals.—Nature (Nov. 7) states that about 1829 some indi- 
viduals of the buffalo (Bos bubalus) were landed at Port Essington, and 
that at the present time the increase of these specimens has resulted in 
the existence of immense herds in certain parts of North Australia. 
The columns of JVature have recently contained quite a controversy 
upon the discovery of the existence of true teeth in the jaw of the young 
Ornithorhynchus.. This discovery is claimed by Mr. Poulton, and the 
structure of the teeth has been described by Mr. Oldfield Thomas. 
The reference to the teeth of both the young and the adult Duck-bill 
in the works of Sir Everard Home is asserted to have been solely to the 
horny plates which eventually take the place of the true teeth, and to 
the changes that take place in them. 
The last volume issued by the venerable cetologist, P. J. Van 
Beneden, restricts the number of European Cetacea to twenty-six, of 
which seven are whalebone whales, and five ziphioids. 
In the Quarterly Journal of the Microscopical Society A. W. Hu- 
brecht gives the results of his studies upon the placentation of the 
hedgehog. The phenomena of placentation are more complex than in 
the ungulates, and lead up directly to those exhibited by the primates ` 
and man. But as the Insectivora are now pretty generally regarded as. 
the most primitive of the monadelphous mammals, this takes away the 
importance of the division into Deciduata and Adeciduata. The Un- 
gulata are certainly adeciduate, but among the Edentata some genera 
are deciduate and others adeciduate: the lemurs are also non-deciduate. 
