PRE-CAMBRIAN LIFE 6 1 



which show at least that their ahmentary arrange- 

 ments were similar to those now in force. If any 

 of the problematical " Conodonts " discovered by 

 Pander in the Cambrian of Russia belonged to 

 marine worms, this inference would be extended 

 back to the Lower Cambrian, so that if the evidence 

 of structure anywhere remains we may hope to 

 find that the pre-Cambrian worms were not inferior 

 to their more modern successors, perhaps even 

 that in this early period, when they probably 

 played a more important part in nature, they were 

 of higher organization than in later times. 



The evidence as to pre-Cambrian mollusks, so far 

 as it goes, is even more curious. The little shell 

 called Volborthella, so far as can be judged from its 

 form and internal structure, is a miniature repre- 

 sentative of these straight Nautili, the Orthoceratites 

 of the Ordovician and later Palaeozoic rocks ; and no 

 one doubts that these latter belong to the highest 

 class of the Mollusks, a class approaching in the 

 development of nerve system and sensory organs to 

 the Vertebrates themselves. This tiny member of 

 the great class of Cuttle-fishes may perhaps have been 

 more nearly allied to the modern Spirula than to 

 the Nautilus. In any case, if, as seems altogether 



