432 THE AMERICAN. NATURALIST.  {VoL. XXXIII: 
a pupil that the images on their retinas are formed by this opening 
rather than by the lens, which is thus in a measure functionless. 
Most vertebrates are unable to accommodate their eyes so that 
they can see equally well in water and in air. Water animals when 
in the air are extremely shortsighted ; air-inhabiting forms when in 
water are very farsighted. Only some few vertebrates, such as the 
pond turtles which seek their prey both by land and water, seem to 
see well on land and yet accommodate for near vision in water. 
Those animals that accommodate by moving their lenses (cephalo- 
pods, fish, amphibia, and some snakes) presumably suffer no special 
loss of this power as age advances. Those whose accommodation 
depends upon a change in the form of the lens, brought about through 
its elasticity (most reptiles, birds, and mammals), probably suffer as 
the human being does, and become permanently farsighted as age 
advances. G A P 
The Sense of Hearing is the subject of a popular discourse deliv- 
ered by Dr. K. Vohsen! before the Senckenberg Natural History 
Society and published in their proceedings. The speaker calls atten- 
tion to the relation between speech and hearing, and shows in a table 
the zoölogical distribution of sound-producing and sound-perceiving 
organs. While almost all animals possess the latter, only arthro- 
pods and vertebrates possess the former. The auditory vesicles of 
the invertebrates, as well as the inner ears of the vertebrates, are 
described. Only a hint is given that the so-called auditory organs of 
_ the lower animals may also be concerned with the function of equili- 
bration, and no mention is made of the fact that, in the cases most 
carefully examined, equilibrations seem to be the exclusive function 
of these parts. The lecture contains an excellent table showing the 
range of hearing in the human ear, and the complex question of the 
analysis of sound by the ear is considered. Gr ae 
Physiology for Schools. — In a little book of Laboratory Exer- 
cises” Mr. James Edward Peabody has done a good work, for which 
many teachers will be grateful. By series of skillfully framed ques- 
tions upon objects readily accessible, the pupil is led to exert his 
1 Vohsen, K. Uber den Gehorsinn, Bericht d. Senckenberg. naturf. Gesell., 
1898, pp. 91-112. 
2? Peabody, J. E., Instructor in Biology in the High School for Boys and Girls, 
New York City. Ladoratory Exercises in Anatomy and Physiology. New York, 
Henry Holt & Co., 1898. Cloth, x + 78 pp., interleaved. 
