Natural-Historical Collections. 67 
On frightening away a throstle, which he had seen engaged in breaking - 
something which it held in its beak against a stone, he found one of the small 
heaps of whelks, among which was a fresh one, newly broken, and containing the 
animal. It may appear extraordinary that a bird possessed of so little muscular 
power should be able to break so thick and hard a shell. Throstles, it is well 
known, break the shells of snails, but these are very fragile; whereas a smart 
blow of a stone or hammer is required to break a periwinkle ; nevertheless the 
matter becomes more credible when we find, by experiment, that a very slight 
force is necessary for breaking a whelk, when it is thrown against a hard body ; 
and that the shell is fractured, when allowed to fall on such a body from a height 
_ of four or five feet. 
Notice of the different causes of the Coloration of Snow and Ice.—De Saus- 
sure first remarked the red coloration of snow on the Brevent in Savoy in 1770. 
The same phenomenon has since been observed by Mr. Ramond in the Pyrenees, 
by Sommerfeldt in Norway, and in the Italian Alps and the Appenines by seve- 
ral naturalists. 
But red snow, very frequent in the polar regions, fixed the attention of the late 
British travellers ; and the specimens which they brought from their voyages, 
submitted to the examination of the most celebrated botanists and chemists, be- 
came the subject of extensive research, and gave much celebrity to this singular 
substance. 
This red snow often covers a great extent of territory. Captain Ross says that 
mountains of about eight miles in length, and 600 feet in elevation, were covered 
with it, and that it penetrated sometimes to 10 or 12 feet in depth. 
The chemical researches of De Saussure, De Sementini, Wollaston, and The- 
nard, only proved that this matter consisted principally of an organic substance, 
analagous to that of some vegetables. 
Francis Bauer was one of the first naturalists who subjected it to microscopic 
examination. He concluded, from his researches, that the globules which form 
this substance, are analogous to those which form the parasitic fungi of the genus 
Uredo, and he gave it the name of Uredo nivalis. His data to establish this 
Singular relation, were principally the existence of little pedicelli sustaining cer- 
tain globules: pedicelli which no one has since been able to perceive. 
Mr. R. Brown established the relationship of this substance with the Tremella 
cruenta, (ing. Bot.) near which the generality of botanists now place it. 
At the same epoch, Baron Wrangel was describing, in the Memoirs of the 
Academy of Science at Stockholm, a red cryptogamous plant which he had ob- 
served upon the rocks in the north of Sweden, and which he designed under the 
appellation of Lepraria kermesina. The odour of violets, which this substance 
emitted, led him to suppose that it had been confounded by Linnzus with his 
Byssus jolithus. 
Mr, Agardh having had occasion, in 1823, to subject to a comparative exami- 
nation the red snow brought from the Pole by our navigators, and the Lepraria 
kermesina, became assured of the identity of these two cryptogamous plants, and 
thought that its analogy with other substances differently coloured, would lead to 
the colouring matter of snow being placed among the most simple alge: he made 
a particular genus under the name of Protococcus. 
Dr. Hooker differs very little from this opinion, in placing this cryptogamous 
plant in the genus Palmella, which approaches very nearly that of the Protococ- 
cus; and Fries, in his Systema Mycologicum, proposes that a genus should be 
formed with several other species of Palmella, under the name of Chlorococcum. 
We thus see that those botanists who have most occupied themselves with this 
question, and in general with the classification of cryptogamous plants, only differ 
about the generic limits which must be established between this plant and those 
which most resemble it. 
The Protococcus nivalis differs essentially from the Palmeila only in as much 
as, that the red globules which give it its distinctive colour are placed upon a 
gelatinous base, and not immersed in that matter, as in the Palmella 

