5 * 
Notes. 
[January, 
It appears that no beautiful or useful organic species, animal 
or vegetable, becomes naturalised in any country without human 
intervention, whilst the noisome and the ugly contrive to extend 
their range in spite of man’s efforts to the contrary. 
The “ American Naturalist ” records a peculiar bellows-like 
structure of the anthers of Rhexia Vivginica, by means of which 
the pollen is actually blown out upon the body of a visiting 
insedl. 
M. H. Viallanes (“ Comptes Rendus ”) communicates very in- 
teresting results on the post-embryonic development of the 
Muscidse. The tissues of the larva are destroyed before the 
adult animal is formed, and at a certain point of time the pupa 
has a true embryonic character. The entire skin of the body is 
destroyed by the degeneration of the hypodermic cellules, so that 
the animal is merely bounded by a thin cuticle. On cutting open 
the abdomen of a pupa of from two to four days, we find the 
body composed merely of two layers of cellules ; the one forming 
a solid chain composed of the epithelial cellules of the digestive 
canal reverted to the embryonic state, and the other at the cir- 
cumference formed by embryonic cellules derived from the mus- 
cular nuclei and the cellules of the adipose tissue. 
According to Mr. Francis Darwin the phenomenon of circum- 
nutation can be distinctly traced in the Phycomyces. 
Mr. A. Tylor (“ Geological Magazine ”) calculates that the 
denudation of the land by rivers and the sea, with the present 
rainfall, is equal to one foot in a thousand years, and in the 
Pluvial period ten times as great. Hence the deltas of all our 
great rivers are later than Post-pliocene, and of the age of the 
Pluvial period. 
Mr. Clement Reid, F.G.S. (“ Geological Magazine ”) combats 
the views of Mr. Howorth as to the sudden extinction of the 
mammoth in Siberia. He considers it evident that the mammal- 
iferous deposits in that country cannot have been frozen all at 
once, or through radiation from the present surface, as there are 
numerous sheets of clear ice, which must have been successively 
formed, interstratified with the ice. 
Dr. Merrill (“ Forest and Stream ”) states that, according to 
the belief of certain Indian tribes, certain s wall birds effeCt their 
migrations upon the backs of larger ones, such as the sandhill 
crane, the white crane, and the Canada goose. 
Mr. J. A. Allen (*‘ Scribner’s Magazine ”) gives the following 
conclusions on the migrations of birds : — That the habit of mi- 
gration resulted from changes of climate, occurring at a not very 
remote geological period ; that every gradation occurs between 
species the most widely roving and such as are stationary, and 
that even members of the same species may be either migratory 
