12 
portion. The light of the room was so controlled by an opaque curtain 
that its intensity could be varied. A sixteen candle power electric 
light was so placed that it illuminated one half of the aquarium. The 
larvae were then placed in this portion. In a short time, less than 
thirty minutes, these larvae were all in the darker portion. The same 
results were obtained by using an arc-lamp. The experiments with 
both daylight and artificial light in varying degrees show that the 
larvae are negatively phototropic. 
If the decapitated larvae are unable to escape a bright light, they 
almost invariably orient themselves in such a manner that the light 
falls with equal intensity upon the lateral halves of the body. A sharp 
pencil of rays of either sunlight or electric light when thrown upon 
the tail causes a quicker response than when concentrated upon any 
other part of the body. 
An attempt was made to ascertain the color discriminating capacity 
of the decapitated larvae. As in the earlier experiments they were 
kept in a large glass aquarium beneath which were placed pieces of 
white, black, red, yellow, green and blue paper. The daily counts 
made over a period of one month showed nothing definite beyond 
the facts earlier recorded viz. The larvae were most frequently found 
on the colors in the half of the spectrum toward the violet end. 
The observations show that the decapitated larvae react toward 
light and colors in essentially the same manner and to the same degree, 
as the normal. The inference is that when the young Necturus is 
deprived of the use of its eyes the dermatopteric sense is adequate 
for its orientation to light. 
Summary. 
The general growth of the decapitate larvae is somewhat slower 
than the normal, but the differentiation of organs, as far as can be 
determined from surface views, goes on at the same relative rate as 
in the normal. 
The movements of the decapitated larvae are less frequent than 
are those of the normal, otherwise they are essentially the same. 
The distribution of pigment is the same in the decapitated as in 
the normal, although the chromatophores are greatly contracted. The 
first bands of pigment coincide with the large dorso-lateral veins. 
The other bands and areas, however, bear no relation to blood vessels 
either in place of origin or direction of progress. The distribution 
