legs are very strong, and
when going at full speed the jerboa takes jumps that measure from
eight to ten yards, according to the unanimous testimony of various
witnesses.

The jumping mouse of North America, which is somewhat larger than an
ordinary mouse, is, according to Brehm, also as swift as an arrow or a
low-flying bird. This exceptional velocity is not all that reminds us
of a bird, for there is also a strong resemblance in the formation of
certain parts of the bodies of the two creatures; but, after
consideration, this should not seem strange, because in animal
organisms similar means are employed to accomplish similar ends. It is
only natural that there should be peculiarities in the construction of
the limbs and skulls of the Dipodidea with their bird-like movements
and bird-like sharp-sightedness, that are usually found only among
birds. The consistency between the construction of their bodies and
their mode of life is a beautiful example of fitness; only by
extraordinary quickness of movement and sagacity could the little
defenseless plant-eaters maintain the struggle for existence in the
barren steppes and deserts. The formation of the bodies of the
different members of the family varies according to their needs. The
jerboa is the largest member of the family. Very little is known of
his life when free; it being known only that the jerboas are widely
spread over the whole of southern Africa, and are nocturnal burrowers
of the steppes. During the rainy season they remain in a sort of
winter sleep.--_Dr. L. Heck, in the Illustrirte Zeitung_.

* * * * *

NEW OBSERVATIONS ON THE LANGUAGE OF ANIMALS.

By M. DE LACAZE DUTHIERS, of the Institute of France.

I had occasion in a note published several years ago in the _Revue
Scientifique_ to mention a parroquet which I have since continued to
observe, the manifestations of whose intelligence are both interesting
and instructive. Many acts of birds are difficult of interpretation.
To speak only of their songs, the meanings of most of the innumerable
varieties of sounds which they produce, and of their diverse
warblings, escape us completely. It is not possible to find the
meaning of these things except by forming suppositions and hypotheses,
or by catching the connections between cries and acts. But instances
of the latter kind are extremely rare in comparison with the great
majority of the manifestations made by animals.