100 
Notices of Books. 
[January, 
Among the recorded fadts to which we may here briefly call 
attention is the hypsometric distribution of the Mollusca. It 
has long been known that on the slopes of mountains each spe- 
cies of plant has its peculiar zone, below or above which it does 
not prosper. A similar rule holds good with the terrestrial and 
fluviatile Mollusca. In the Central Pyrenees and the Alps 
M. P. Fischer has recognised five zones, each characterised by 
a species of Helix. 
The subject of “ seasonal dimorphism ” receives notice. 
Certain insect forms, lately regarded as distinct species, are now 
found to be merely varieties, dependent upon temperature or 
upon the time of the year at which they appear. Chrysalids 
of P. marcellus, if exposed to severe cold in an ice-house, be- 
came P. Telamonides. Certain Australian moths, unlike ordinary 
Lepidoptera, do not suck the honey from flowers, but perforate 
fruits to feed upon the juices. For this purpose their proboscis 
is strong and sharply pointed. 
According to Dr. Otto Hahn the much-disputed Eozoon Cana- 
dense is a “ myth founded on a mistaken conclusion as to the 
micro-geological character of certain serpentines.” If this state- 
ment is true it will be a heavy blow and great discouragement 
to Principal Dawson and other surviving members of the 
Cuvierian school. At the same time the Bathybius is becoming 
extremely questionable. It appears to be little more than a floc- 
culent deposit of sulphate of lime. 
An extracft from the “ Transactions of the Norfolk and 
Norwich Naturalists’ Society” gives the “ dimensions of some 
of the famous and larger oak-trees in England.” With all defer- 
ence to the Society we believe it would not be difficult to seleCt 
oaks larger than many which they have described. We m&y in- 
stance the “ Major” and the “ Shambles” oaks, in Sherwood; 
the “ Shire ” oak, at the junction of the counties of York, Not- 
tingham, and Derby; and the “ King” and “ Queen ” oaks, in 
Dunham Massey Park, in Cheshire. 
A paragraph, the origin of which has been accidentally omit- 
ted, states that “A comparison of the observations of naturalists 
with the weather-charts published in Europe and America makes 
it now seem certain that the weather immediately prevailing, 
and not that which is about to come in the near future, is the 
element which decides the movement of the greater number of 
migratory birds.” This observation strips the migration of 
birds of no small part of the mystery in which it has been 
wrapped by unscientific writers. 
The decrease of the birds of Massachusetts, both as regards 
numbers and species, has been examined by Mr. J. A. Allen. 
The mischief, for such it is, is ascribed in part to wanton 
shooting. 
The well-known water-weed, Elodea Canadensis, is described 
by MM. Stein and Hanstein as having the power of evolving 
