772 NEW YORK STATE MUSEUM 



PLATE 18 



Genus didymograptus McCoy 



See pi. 14, 16 



Didymograptus nitidus Hall (sp) 



Page 671 

 See pi. 14, fig. 6, 8 



1 Large rhabdosome 



2 Branch, obliquely compressed 



3 Typical specimen 



4 Rhabdosome with slightly declined branches 



Graptolite bed 2 of the Deep kill section 



Didymograptus nitidus Hall, var. grandis var. nov 



Page 674 



5 Most perfect specimen observed 



Graptolite bed 2 of the Deep kill section 



Didymograptus tornquisti sp. nov. 



Page 688 



6 Type specimen 



7 Same, xle, to show more distinctly the character of the thecae 



Graptolite bed 3 of the Deep kill section 



Didymograptus patulus Hall (sp.) 



Page 674 



See pi. 14 



8 Young typical specimen 



9 Nearly mature specimen with central disk 



Graptolite bed 2 of the Deep kill section 



