Influence of the Nervous System 709 
The presence of this regenerated cord quite close to the ampu- 
tated end did not suffice to induce development of a head. 
Where a new head did appear the cerebral gang'ia proliferated 
from an invagination of ectoderm in two directions, (1) dorsally to 
form ganglia proper, (2) ventrally to form the commissures. 
These new and functional heads with their cerebral ganglia 
may develop in the entire absence of motor nerve influences. In 
the three animals where this clearly occurred, the old cord was 
removed from 34, 44 and g segments respectively, and though 
some anterior regeneration of the cord took place, the intervening 
area between this and the amputated end did not contain the 
slightest trace of any part of the cord. 
In the great majority of worms with regenerated heads, the 
brain was connected with a continuous cord, which arose very 
probably by the anterior growth of the cord on the one hand and 
the posterior growth from the anterior “proliferation zone” on the 
other. 
Here we have a second instance where 2n adult animal regener- 
ated an organ without the aid of the :-erve cord, or of motor nerve 
stimuli. 
REGENERATION IN THE STARFISH IN RELATION TO THE NERVOUS 
; SYSTEM 
A few experiments were undertaken with the common starfish, 
Asterias vu ‘garis, to ascertain whether the presence of the nervous 
system is requisite for regeneration. The nervous system in- 
cludes, in the arms at least, (1) a nerve ridge of the apical nervous 
system situated along the roof of the ccelomic cavity, (2) radial 
nerve ridge of the superficial oral system, (3) ridges of the deeper 
oral system. King believed that only the oral nervous system was 
needed in regeneration. For, the oral half regenerated the aboral 
half of the arm, while the reverse was not true. Butthe inability 
of the aboral to replace the oral half may have been due to the 
absence of other systems essential to the formation of the arm. 
For with the oral half there were removed the water vascular, the 
hemal system as well as the oral nerve ridges. Experiments 
