Distribution of the Rhabdophora. 275 



Oedovician System (Lower Silurian of Murchison). 



(a) Arenig Formation. 



fTABLE III. Showing the Range of the Arenig 

 Rhabdophora. 



f These tables include all the forms of Rhabdophora published to this 

 date (Jan. 1880) the geological horizons of which are approximately known. 

 Several species recently described are added to those already enumerated 

 in the preceding portions of this paper. A few are omitted altogether, 

 either because their geological age is uncertain, or because they are of 

 very doubtful specific identification. 



