ORAPTOLITES OF XEW YORK. TAUT 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 Avhich shows a somewhat 



abrupt downward bending of the branches 



20 Normal and approximately mature specimen 



21 Frao-ment of a ^'ariety with Avidely separated branches and dissepiments 



and closely arranged thecae 



22 Fragment of the opposite extreme of variation with closely arranged 



broader branches and dissepiments (var. c o n f e r t u m) 

 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. 



