Wallace's "Malay Archipelago."

Meyer and Doege, on plants of Cape of Good Hope.

Mica, in foliated rocks.

Mica-slate, clay-slate and.

Mice, ears of.
-experiments by Tait on.

Microscope, Darwin on convenient form of.
-indispensable in work on flowers.
-use of compound without simple, injurious to progress of Natural
History.

Migration of animals and plants.
-Darwin on plant-.
-of elephants.
-Glacial period and.
-of plants.
-in tropics.
-of birds.

Mikania, a leaf-climber.
-M. scandens, gradation between Mutisia and.

Mill, J.S., on Darwin's reasoning.
-on greatest happiness principle.

Miller, Hugh, "First Impressions of England and its People."

Miller, S.H., "Fenland Past and Present" by Skertchley and.

Miller, Prof. William Hallowes, F.R.S. (1801-80), held the Chair of
Mineralogy at Cambridge from 1832 to 1880 (see "Obituary Notices of
Fellows," "Proc. R. Soc." Volume XXXI., 1881). He is referred to in the
"Origin of Species" (Edition VI., page 221) as having verified Darwin's
statement as to the structure of the comb made by Melipona domestica, a
Mexican species of bee. The cells of Melipona occupy an intermediate
position between the perfect cells of the hive-bee and the much simpler
ones of the humble-bee; the comb consists "of cylindrical cells in which
the young are hatched, and, in addition, some large cells of wax for
holding honey. These latter cells are nearly spherical and of nearly equal
sizes, and are aggregated into an irregular mass. But the important point
to notice is that these cells are always made at that degree of nearness to
each other that they would have intersected or broken into each other if
the spheres had been completed; but this is never permitted, the bees
building perfectly flat walls of wax between the spheres which thus tend to
intersect." It occurred to Darwin that certain changes in the architecture
of the Melipona comb would produce a structure "as perfect as the comb of
the hive-bee." He made a calculation, therefore, to show how this
structural improvement might be effected, and submitted the statement to
Professor Miller. By a slight modification of the instincts possessed by
Melipona domestica, this bee would be able to build with as much
mathematical accuracy as the hive-bee; and by such modifications of
instincts Darwin believed that "the hive-bee has acquired, through natural
selection, her inimitab