NEW YORK STATE MUSEUM 



figure tlirough a semitransparent covering, if we closely examine the 

 large canal leading from plate 31 to 26. In figure 2"/, from Syntype 



Fig. 26-33 Palaeocystites dawsoni Billings. Figures 26 and 27 are from photomicro- 

 graphs made of Syntype B under a gum dammar mounting. Figure 28 shows the area of 27 as 

 photographed without the mounting. Figure 29 is of the apotype, without mounting. Figures 

 30-33 are from photomicrographs of Syntype A. all with the dammar mounting but from 

 different negatives. For plate numbers see fig. 24 and 25 



B the dammar mounting has left the basins too dark and the sutural 

 canals can not be seen. The same area without the dammar is 

 shown in figure 28 and the difference in results of the two photo- 



