— 455 — 
Lrequently bears, immediately beneath the leaf-scar, a small tubercle 
with circular or subtriangular depression. Fructification borne on 
Halonial branches. 
The description given above for the species is taken from Kidston’s 
valuable memoir on the genus. 
This species, which has been described and illustrated by Zeiller 
from Arroio dos Ratos, in Rio Grande do Sul, is represented in the 
present collection by but afew fragments poorly preserved as moulds 
formed in a layer of natural charcoal and filled with coaly dirt. 
Ilowever, enough can be made out from them to establish their 
agreement with the forms figured hy Professor Zeiller from specimens 
much clearer and better preserved. The species is not yet known from 
any other region of the older Gondwana flora. 
Localities : Roof of the coal near Sd0 Jeronymo, Rio grande do Sul. 
About 20 meters above the Irapudé coal, or 120 meters below the Iraty 
black shale. Lot 3593. Also, in doubtful material, from roof of the 
Sado Jeronymo coal 15 kilometers southwest from Irapud on land of the 
sesmaria do tenente Ricardo. Lot 3594. 
Sigilliaria 
Brongniart, Mus. his. nat., Paris, vol. viii, 1822, p. 209. 
The essential criteria which distinguish the genus Sigillaria 
from Lepidodendron are those furnished by the outer cortex. They 
relate chiefly to the forms and arrangement of the leaf scars and the 
leaf cushions. The genus comprises two large groups, the Bu-Sigillariae 
and the Sub-Sigillariac, and though transitional types render imprati- 
cable the formal distinction of these groups they are in most cases very 
readily separated. 
The Bu-Sigillariae includ two sections: Rhytidolepis, which has 
straight, broad, prominent longitudinal ribs, each bearing a row of 
more or less distant, and in general ovate-hexagonal leaf scars placed 
along a flattened central zone ; and Favularia, in which the less rigid 
ribs are separated by sharp, more or less distinctly zigzag furrows, 
while a transverse line or crease crosses the narrow point of the rib 
(4) Trans. R. Soc. Eiinb, vol. XXXVI, pt. 3, 1893, p 555. 
