ORGANIC DEPENDENCE AND DISEASE 31 
Walcott has brought out a most impressive number and 
variety. 
As to the annelids or worms, speaking in broad and 
familiar terms, while the number of species actually rec- 
ognized from the preserved parts is comparatively small, 
yet the rocks of this age are voluminously marked with 
their trails and borings, and we must conclude that these 
soft-bodied creatures were abundant. Deductively they 
must have been, for on evidence quite independent of fossil 
remains we look to these simply segmented creatures, or to 
some radicle constructed on a like pattern, as the starting 
point for several of the differentiated groups of the 
Cambrian ; the specialized, partly stabilized and partly 
retrogressive bracliiopods, the progressive crustaceans, and 
perhaps the echinoid holothurians and cystids. The worm 
radicle must therefore be very ancient and we have reason 
and evidence to predicate its abundance in the faunas of 
Precambrian time. 
Here then, in essence, we have the significance of the 
Cambrian fauna in terms of its abundance and independ- 
ence, retreat and advance. It enters later geologic stages 
of existence equipped to carry forward its great dependent 
groups to further expansion within the restraints of its in- 
duced limitations and a specialization into more perfected 
adjustments but without hope of any advance that will im- 
prove the grade of life ; and to direct its independent 
groups, its segmented annelids, trilobites and crustaceans 
upward with the promise of quick developments which are 
ancient creatures to those now living and their proper place in the scheme of 
living things; forgetting or overlooking the fact that these designs are nn- 
reckoned millions of years old and are in truth the parents of all such conjec- 
tures. They antedate classifications and the objects classified. Governor Wil- 
liam Bradford, of the Plymouth colony, must have at least ten thousand living 
descendants in this land of ours, rejoicing under various patronymics which 
time and marriage have brought. To which does the old progenitor now be- 
long, Smith, Jones or Robinson? All alike may claim him. 
