IX 
THE MARKINGS OF ORGANISMS 
201 
mark the internal attachment of the muscles. These 
spots are “ centres for aggregation of pigment,” and 
have been supposed to indicate the segmentation of 
the body, and thus, as Dr. M'Cook says, the patterns 
probably bear a direct relation to the segmentation. 
The same facts are observable to a much less degree 
in the cephalothorax, and M‘Cook suggests that the 
annuli round the legs, which occur especially in the 
neighbourhood of the joints, may be determined in a 
similar way by the arrangement of the muscles. All 
this is exceedingly interesting and suggestive, but 
from a study of other forms, eg. insects, one would 
expect to find that the gradual disappearance of 
marked segmentation in spiders was associated with 
a profound modification of the coloration. If, as 
there is reason to believe, coloration and structure are 
directly associated, then the new structural characters 
of the body should be reflected in the markings. 
It seems probable that this really occurs. Thus 
Argiope argyraspis has on the abdomen two longi¬ 
tudinal yellow lines and thirteen unbroken transverse 
black lines as well as other incomplete ones. Now 
as the embryos in spiders are commonly supposed to 
have ten to twelve abdominal segments at most, and 
as the posterior ones degenerate during development, 
it is at least unlikely that these transverse bars have 
a direct relation to segmentation. It seems more 
probable that we have another instance of the fact 
that in specialised organisms the process of integration 
which has so profoundly modified the segmentation 
has been accompanied by changes in the colour- 
markings. 
In butterflies, beetles, and other insects with large 
