Distribution of the Rhabdopliora. 

 Table X. {continued). 



19 



Ordovician. 



Upper. 



3 



Silurian. 



Lower. 



Middle. 



Dicellograptus moffatensis, Carr. 



Morrisi, Hopk 



patulosus, Lapw 



sextans, Hall 



pumilus, Lapw 



Dicranograptus Clingani, Carr. . 



forinosus, Hopk 



Nicholsoni, Hopk , 



ramosus, Hall 



ziczac, Lapw 



Family IV. Dichograptid^:. 



i. (type D. Murchisoni, Beck). 

 Didymograptus bifidus, Hall . . . . 



indentus, Hall 



, var. nanus, Lapw 



minutus, Tornquist 



Murchisoni, Beck 



, var. furcillatus, Lapw. 



, var. geminus, His. . . 



ii. (type D. v-fractus, Salter). 

 Didymograptus balticus, Tullbery, 



vacillans, Tidlberg 



v-fractus, Salter 



Pantonii, 3fi Coy 



iii. (type D. patulus, Hall). 

 Didymograptus constrictus, Hall 



extensus, Hall \. . . 



, var. euodus, Lapw. . 



nitidus, Hall 



patulus, Hall 



similis, Hall 



superstes, Lapw 



suecicus, Tullbery 



2* 



