GRAPTOLITES OF NEW YORK. PART 1 749 



18 Young, more advanced rliabdosome, compressed somewhat obliquely and 



thereby showing the cruciform initial portion and the absence of dis- 

 sepiments in the latter 



19 Same view of a still more advanced rhabdosome which shows a somewhat 



abrupt downward bending of the branches 



20 Normal and approximately mature specimen 



21 Fragment of a variety with widely separated branches and dissepiments 



and closely arranged thecae 



22 Fragment of the opposite extreme of variation with closely arranged 



broader branches and dissepiments (var. confertum) 

 All specimens are from the upper Cambric Dictyonema shale at Schagh- 

 ticoke, Rensselaer co. N. Y. The originals are in the New York State 

 Museum. 



