148 GEORGE E. NICHOLLS 
quently followed by a period of marked activity. In this case 
the animal would dash about the tank, commonly blundering 
heavily into the confining walls. This phase rarely endured for 
long, but gave place to a quiescent stage in which the animal 
apparently exhibited a preference for the darker part of its tank. 
Settling down, it might remain inactive for comparatively long 
periods, moving only when disturbed. In other cases the speci- 
men, recovering from the anaesthetic, passed directly into this 
lethargic condition. I imagine that this difference in behavior 
was due to the varying degree in which the animal had been 
affected by the anaesthetic, a slight degree of insensibility being 
marked by the erratic activity when volition was recovered. 
Be this as it may, the assumption of some posture of the body 
unlike that which I have described above as normal, was fre- 
quently manifested very soon after the quiescent stage was 
reached. In some cases it appeared within ten minutes of the 
operation. Both the head and tail would be gradually lifted 
until the long axis of the body, from being a straight line would 
become markedly curved (figs. 2-5). The tail was, in general, 
sharply upturned from its base, while the trunk region was up- 
lifted upon the pectoral fins from a region just behind the head. 
In the rays, owing to the great development of the pectorals, 
this appears to give rise to a transverse curvature of the anterior 
part of the body, as seen from in front (figs. 9, 13, 14). 
There may be also a distortion of the long axis in the hori- 
zontal plane, the trunk and tail being bent several times from side 
to side (in some of the dogfishes) or with a single sharp bend of 
the hinder part to one side (rays and dogfish). 
It is probable that a disturbance of the poise of the body 
exists, ikewise, while the animal is in motion. It is, however, 
very difficult to be sure of this. In some of the dogfish, certainly, 
uniform undulation of the body in swimming seemed to be re- 
placed by a less even movement which is perhaps best described 
as a wriggling action. 
These reactions did not always make an appearance quickly 
after the operation. In some cases their advent was delayed for 
days even, and in yet others, as will be seen from the detailed 
