330 SCIENCE PROGRESS. 



still further light upon the shape of this primitive form, for 

 we should be justified in assuming that the exact method of 

 distortion of the early undifferentiated segments was in the 

 main that which still persists in Galeodes. As a matter of 

 fact, then, we do know that the method of feeding of 

 Galeodes was the primitive method. All the principal 

 Arachnids still seize and crush their prey with either the 

 first or the first and second limbs, which are thrown 

 forward round the mouth, and the juices are sucked out. 

 I say all the principal Arachnids, for in some of the more 

 specialised groups, the Harvestmen, and the Mites, the 

 type may here and there be departed from. But even in 

 these forms it persists with sufficient frequency to justify us 

 in concluding that this method of feeding was first acquired 

 by the ancestral Arachnid from which all the existing 

 derivative forms must have inherited it. So much indeed 

 we could have arrived at without the assistance of the 

 Galeodidae, but it is doubtful whether we should ever 

 have unravelled the actual mechanical distortion of the 

 segments which led to the initial differentiation of the 

 primitive Arachnid from its more simply annulate ancestors, 

 but for the persistence of a form which has never added to 

 the primitive number of fused segments. 



What then was the nature of this primitive distortion 

 of the three anterior segments, so far as we can gather it 

 from the conditions found in Galeodes? Our analysis leads 

 to the following conclusions : — 



1. The segments were at one time simple annular 

 segments like those along the rest of the body ; the mouth 

 opened on the anterior face of the first segment ; a large 

 fleshy prostomium or upper lip protruded anteriorly above 

 the mouth ; and from the side of each segment a pair 

 of simple limbs, richly covered with bristles, projected 

 laterally. That is this analysis takes us back to a simple 

 Chaetopod Annelid. 



2. This simple condition was first departed from by the 

 bringing forward of the first pair of limbs to the sides of 

 and slightly above the mouth. The two limbs, thus 

 arranged side by side at the anterior end of the body, not 



