1906-7.] Internal Structure of Sigillaria mamillaris , etc. 205 
when describing the next species that these can only be regarded as the 
leaves of Sigillaria. 
Sigillaria scutellata, Brongniart. 
The specimen of this species is more perfect than that of Sigillaria 
mamillaris , the complete cylinder of the cortex being preserved, and]the 
vascular axis, though compressed, remaining unbroken. 
Fig. 2. — Sigillaria scutellata, Brongt. Portion of xyleni ring, a , protoxylem of primary 
xylem b , secondary xylem c x 90. 
The stem has a circumference of 15 '50 cm., and contains twenty-two jibs, 
but the stele has only a circumference of about 2 cm. This specimen brings 
out very prominently the small size of the vascular axis when compared with 
the circumference of the stem. The same characteristic has been already 
observed in Sigillaria elegans and in the Lepidodendracece. 
The closed ring of xylem in Sigillaria scutellata has only attained 
a width of about 0 - 90 cm., of which the primary xylem forms rather less 
than half. 
The outer margin of the primary xylem is. very feebly crenulated, and 
in some places it is difficult to separate the various groups of protoxylem 
