52 
BULLETIN of the bureau of FISHERIES. 
the lateral nerve is exposed and directly stimulated electrically precisely these move- 
ments occur. They also occur if the lateral line on the surface of the body is stimulated 
electrically. But none of these movements take place if previous to the stimulation of 
the regions mentioned the spinal cord is destroyed. If the spinal cord of the dogfish 
is destroyed from the tail to the neck region and the animal allowed to recover, no 
amount of stimulation of the lateral line or its nerve in the region in which the cord has 
been destroyed will, in my experience, call forth the fin movements described by Lee; 
but if the lateral-line nerve is cut anteriorly these movements may be induced by 
stimulating any spot along the appropriate side of the body, provided the stimulus is 
applied anterior to the pelvic fins. Thus the responses described by Lee depend on a 
stimulation of spinal nerves, not of lateral-line nerves. As Lee nowhere states that he 
took steps in his experiments to eliminate the spinal nerves, I suspect that he mistook 
reactions dependent upon these nerves for true lateral-line reactions. Thus the evi- 
dence that he has brought forward for the equilibrium function of the lateral-line organs 
falls to the ground. 
Although the lateral-line organs, in my opinion, do not influence the fin movements 
in the way that Lee believed, they are capable of effecting important responses. If the 
skin of a dogfish whose spinal cord has been destroyed is pressed upon above or below 
the lateral line, no reaction occurs; if, however, the pressure is brought to bear on the 
lateral line itself, there is a considerable slowing in the respiratory rate or even a tem- 
porary cessation of movement. This respiratory response can also be obtained when a 
current of water is played on the lateral line, but it disappears permanently on cutting 
the lateral-line nerve. With the lateral-line system intact it is, however, so invariable 
in its occurrence that I believe that pressure may be regarded as one of the normal 
means of stimulating this system. This view has already been advanced by Fuchs 
(1894) as a result of his experiments on Raja. 
The influence which the lateral-line organs of the dogfish have on its respiratory 
rate is not limited to the side stimulated. A stimulus applied either to the right lateral 
line or to the left one will effect a change in the whole respiratory mechanism. 
The experiments thus far carried out show that the lateral-line organs of the dogfish 
are stimulated by vibrations of low frequency and by simple pressure, both mechanical 
forms of stimuli, and that these organs can influence the respiratory rate and the loco- 
motion of the animal, but not in a way especially concerned with equilibrium. 
the ampullae of lorenzini. 
The head of the dogfish is marked with symmetrically placed clusters of minute 
pores which are often mistaken for lateral-line pores. Each of these pores opens into 
a long, narrow tube which makes its way below the skin and ends in a bulb-like enlarge- 
ment. These are the ampullae of Lorenzini. They have long been suspected of being 
related to the lateral-line organs, an opinion that is supported by their innervation. 
So far as I am aware, no experimental evidence has thus far been obtained concerning 
their function. As the region in which they occur is covered with a skin filled with 
