BRACHIOPODA. 



35 



The presence of the median septum establishes another line of connection 

 with the post-palaeozoic members of the genus Spiriferina, while the punctation 

 of the epidermal layer only, retains these fossils in close association with the 

 glabrate Spirifers. 



The following table will afford a summary of the foregoing classification as 

 far as it relates to the North American Spirifers. The names of species of 

 which specimens have been examined stand in Roman text ; those which have 

 been placed in the grouping from a study of descriptions and illustrations only, 

 are in italics ; others, in regard to whose relations it has seemed unwise to ex- 

 press an opinion on account of the insufficiency of our knowledge, are omitted. 

 Any names of extra-limital species stand in brackets. 



I. Radiati: 



1 . Pauciplicati : 



S. radiatus, Sowerby, 



S. Eudora, Hall, 



S. Meta, Hall, 



S. Foggi, Nettelroth, 



S. rostellum, Hall and Whitfield, 



S. macropleura, Conrad, 



Clinton and Niagara groups. 



Niagara group. 



Niagara group. 



Niagara group. 



Niagara group. 



Lower Helderberg group. 



II. 



2. Multiplicati : 



S. Niagarensis, Conrad, 

 S. asperatus, Ringueberg, 

 S. Tullius, Hall, 

 S. Belphegor, Clarke, 

 S. mesastrialis, Hall, 

 S. sp. indes., 



3. Dupliciplicati : 



S. nobilis, Barrande, 

 [S. Schmidti, Lindstrom, 



Lamellosi : 



1. Septati: 



S. sulcatus, Hisinger, 

 S. perlamellosus, Hall, 



Niagara group. 

 Niagara group. 

 Hamilton group, 

 Genesee shale. 

 Chemung group. 

 Lower Carboniferous. 



Niagara group. 

 Wenlock limestone.] 



Niagara group. 



Lower Helderberg group. 



