18 
Explanation of Plate IV 
Cryptophragmus antiquatus Raymond. 
Figure 1. 
“ 2 . 
" 3. 
“ 4. 
“ 5 . 
A transverse section, not at right angles to the axis. X 3. 
A transverse section at right angles to the axis, shows the inner tube 
with definite wall, a “clear zone,” then a pore-pierced sheath zone, 
a lime-mud filled structureless zone, and finally an outer sheath 
zone. Notice the papillate nature of the outer surface where the 
specimen is still in contact with the matrix, and note that the 
elevations are at the apertures of the tubes, and not at the tube 
walls. Also that the tubes are filled with calcite and not with 
mud. X 3. 
A rather badly preserved transverse section. X 3. 
A transverse section in which the vesicular wall of the inner tube 
is especially well presented. X 3. 
A specimen in which the inner tube only is preserved, the sheaths 
being entirely destroyed. Such specimens are very frequently 
found, £ natural size. 
