ine of
evolution, and upon it is based the law of progressive psychical
development from the simple manifestations of conscious determination
in the lowest organisms to the most complex operations of the mind in
man.

The queerest of all queer-eyed animals is, probably, the Periophthalmus,
a fish inhabiting the coasts of China, Japan, India, the Malayan
Archipelago, and East Africa.[16]

[16] Semper, _Animal Life_, p. 374 _et seq._

I use the word coasts advisedly, for this strange creature when in
pursuit of its prey leaves the sea and comes out on the sands, thus
existing, for the greater portion of its life, in an element which,
according to the general nature of things, ought to be fatal to it. The
laws of evolution have, however, eminently prepared it for its peculiar
mode of life, for its gill-cavities have become so enlarged that when it
abandons the sea it carries in them a great quantity of water which
yields up the necessary supply of oxygen.

Its locomotion has been provided for likewise, for continued use along
certain lines has so developed its pectoral fins that the creature uses
them as legs, and jumps along at a surprising rate of speed.

Its eyes are very large and prominent, and possess, for a fish, the
peculiar faculty of looking around on all sides, hence its name,
"periophthalmus," which is derived from the Greek words, [Greek: peri],
around, and [Greek: ophthalmos], eye. These eyes are situated on top of
the animal's head, and present a very grotesque appearance.

The favorite food of this fish is Onchidium, a naked mollusk. And, in
the matter of eyes, this last-mentioned creature is itself worthy of
remark. Its cephalic, or head, eyes are like those of other mollusks of
its genus, and are not worthy of special mention, but its dorsal eyes,
sometimes several dozen in number, are truly remarkable. These eyes,
although they are very simple in structure, in type are the same as
those of vertebrates, having corneae, lenses, retinae, and "blind spots."
(In the vertebrate eye, the spot where the optic nerve pierces the
external layer of the retina is not sensitive to light impressions;
hence, it is called the "blind spot.")

When this mollusk sees periophthalmus bounding over the sands (and that
it does see is beyond all question), what does it do? It contracts a
thousand or so of little bladder-like cells in the skin of its back,
thereby discharging a hailstorm of minute concretions in