296 JELLY-FISH, STAR-FISH, AND SEA-URCHINS. 
~The only other experiments in nerve-section to 
which the simple anatomy of a Star-fish exposes 
itself is that of dividing the nerve-ring in the disc; 
or, which is virtually the same thing, while leaving 
this intact, dividing all the nerves where they pass 
from it into the rays. In specimens mutilated by 
severing the nerves at the base of each of the five 
rays, or by dividing the nerve-ring between all the 
rays, the animal loses all power of co-ordination 
among its rays. When a common Star-fish is so 
mutilated it does not crawl in the same determinate 
manner as an unmutilated animal, but, if it moves 
at all, it moves slowly and in various directions. 
When inverted, the power of effecting the righting 
manceuvre is seen to be gravely impaired, although 
eventually success is always achieved. There is a 
marked tendency, as compared with unmutilated 
specimens, to a promiscuous distribution of spirals 
and doublings, so that instead of a definite plan of 
the manceuvre being formed from the first, as is 
usually the case with unmutilated specimens, such 
a plan is never formed at all; among the five rays 
there is a continual change of un-codrdinated move- 
ments, so that the righting seems to be eventually 
effected by a mere accidental prepotency of some of 
the righting movements over others. Appended is 
a sketch of such un-coordinated movement, taken 
from a specimen which for more than an hour had 
been twisting its rays in various directions (Fig. 57). 
Another sketch is appended to show a form of 
bending which specimens mutilated as described 
are very apt to manifest, especially just after the 
