i io OUR COMMON BRITISH FOSSILS. 



nites and the sea-urchins is bridged over by a large 

 number of intermediate generic forms. Still more 



Fig. 91. Pentacrinus briareus : a, common Liassic Encrinite ; , upper 

 surface of body. 



remarkable is the fact illustrated by Haeckel and 

 others, that the young of all the Echinoderms, like 



