RAYS 250

a weapon amongst the Polynesian islanders, and, like
the horn of the narwhal and the sword of the xiphias,
is frequently found buried in the timbers of ocean-
going ships. Notwithstanding its name (Pristis
antiquorunt), the saw-fish is not as old in time as the
sword-fish, for it first appears in the London clay.

The electric rays (7 orpedinide) bear a familiar
name in modern warfare. There are six species of
torpedo, who all kill or stun their prey by an electric
shock, three of them being natives of the Mediter-
ranean. The true rays are found in all temperate
seas, though most of them as yet come from the
northern hemisphere. On our coasts the most fre-
quent forms are the thornback (Raza clavata) and
the common skate (R. datis). Some of the skates
are giants, measuring seven feet across. The sting-
rays belong to another group, the Zrygonide. The
eagle-rays belong to yet. another, the Mylhobatide,
these having the greatest fin-spread of any of the
fishes, specimens measuring twenty feet in width
being on record. They are the last of the living
things called vertebrate.

With them we end our survey of the aristocrats
of animal life. Below them are the great majority
from whom it is impossible to separate the higher
classes, and from whom, through many a transition,
they have undoubtedly risen in that great system of
orderly growth under which Creation has attained its
present state. Such a thing as chance or isolation in
their history is inadmissible. As Professor Marshall
says, in his Vertebrate - Embryology, ‘ All animals