274 Ber ridge . — On Two New Specimens of Spencerites insignis. 
The protoxylems of the woody cylinder are about twenty in number, 
this corresponding to the number of orthostichies of sporophylls. The 
prominence of the angles of the stele formed by the protoxylems varies 
considerably at different levels in the axis. When the section passes near 
the level at which a whorl of ten leaf-traces leaves the stele, ten angles 
are much more clearly marked than the other ten alternate with them ; 
this probably accounts for the fact that ten is given as the number of 
protoxylems in Dr. Scott’s paper. 
Fig. 2. Transverse section of the axis, showing the two zones of the outer cortex, and two 
alternating whorls of leaf-traces, in, pith; x , xylem ; ix., inner cortex; o.c., outer cortex ; l.t 
leaf-traces belonging to the outer whorl ; l.t'., leaf-traces belonging to the inner whorl. 
Of the zones of tissue surrounding the wood only the inner and outer 
layers of the cortex remain, the phloem and middle cortex having perished. 
The inner cortex consists of thickened, somewhat elongated cells, and is in 
every respect similar to that of previous specimens. 
The outer cortex, however, is evidently very variable in this genus. 
Dr. Scott has taken the specimens showing Dictyoxylon structure as 
typical, but he mentions other cases in which ‘ the cell-walls are considerably 
thickened throughout the external cortex.’ In the present examples it 
appears to be differentiated into two zones ; the outer is uniformly 
thickened, the Dictyoxylon character being absent ; the inner consists of 
