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 brachiopods, 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 un- 

 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. 



