The Ludlovian and Wenlockian ages are subdivisions of this period.  
The Ludlovian and Wenlockian ages are subdivisions of this period.  In the oceans, trilobites flourished while its final years saw the first jawed fish and vascular plants develop. Arachnid and centipede fossils show that organic life first emerged from the sea in the last stages of, for 10 points, which Paleozoic period which lasted from 440 to 410 million years ago and preceded the Devonian.
The Ludlovian and Wenlockian ages are subdivisions of this period.  
Silurian Period