pigmented spots which are supplied with nerves;
in several species, however, I have been able to make out lenses. The
eyes are arranged along the rays or arms, and vary in number.

[9] "In Solaster or Asteracanthion the lenses look like brilliant
eggs, each in its own scarlet nest."--LUBBOCK, _Senses, Instincts, and
Intelligence of Animals_, p. 132 _et seq._

Even the stay-at-home and humble oyster has eyes (not the round, fleshy
muscle called the "eye" by gourmands and epicures, but bright spots
around the edge of the mantle)--primitive eyes, it is true, yet amply
sufficient for the needs of a domestic, non-travelling, home body like
the oyster.

In most of the worms the eyes are simple ocelli--spots of pigment
supplied with nerves. These eyes can discriminate between light and
darkness, which is all that is required of them; but in the Alciope, a
small sea-worm, these organs are brought to a high degree of perfection.
This worm is exceedingly transparent, so that when observing it, it is
difficult to make out more than its large orange eyes and the violet
segmental organs of each ring. It looks like an animated string of
violet disks surmounted by a pair of orange-colored eyeglasses. The eye
of this creature is strikingly like that of a human being; it has a
cornea, an "eye-skin," a lens, vitreous humor (posterior chamber), and
retina.

Another aquatic worm, Myrianida, is still more remarkable, not only on
account of its eyes, but also on account of the wonderful way in which
it reproduces its young. When seen swimming in the water it presents the
appearance of a long, many-ringed worm, which impels itself through and
by the aid of its hundreds of flat, oar-like legs. Closer inspection
reveals the startling fact that this seemingly single worm is really a
multiple worm--six or more individuals being joined together, thus
forming a living chain. This creature reproduces itself by
fissigemation; that is, when the young worms arrive at a certain age
they separate from the parent worm and begin life as individuals. These
in turn eventually become multiple worms and divide into individuals,
and so on _ad infinitum_. The tail worm, or that section farthest from
the head, is the oldest and is always the first to leave its comrades
and take up a separate existence. The adverb _always_ in the above
sentence is, strictly speaking, not exactly accurate, for on one
occasion I saw the separation occur at the second head