Explanation of Plate 1. 



Page. 



Figs. 1, 2. Dendrograptus f problernaticas Spencer 10 



(See also text fig. 6.) 



1. A small rhabdosome, X 1.5, arising from a discoidal bod}'. 



2. A larger example, X 1.5, showing the lax arrangement of the 



branches. 



3. Dendrograptus ramosus Spencer 8 



(See also text figs. 3 and 9. ) 

 Gurley's photograph of the specimen, X 1.5, illustrated on page 7. 



4. Dendrograptus ontarioensh, new species 12 



(See also text fig. 12, ) 

 The type-specimen, X 2. 

 66 



