241 
to be found, running from the base of the seed as far as 
the micropylar region. At the top near the micropyle, 
the sclerotesta has a rhomboidal-shape in transverse section. 
Near the chalaza it rises inside to form a small cushion 
of tissue. 
The nucellus stands free on its base within the testa, 
but it may be, that the cavity between integument and 
nucellus is formed after contraction of the latter. 
The vascular bundle enters the base of the seed through 
an opening of the sclerotesta. On the cushion beneath 
the nucellus it is divided into two branches, lying in the 
principal plane, which after passing the sclerotesta in a 
horizontal direction, bend upwards running through the 
sarcotesta up to the micropylar region, following the 
grooves formed by the valves of the sclerotesta. 
It is still uncertain to which plant Mifrospermum belongs, 
because it is always found without any connection, but 
it is possibly the seed of one of te Cordaitales. 
Bennettitales. 
$ 11. Bennettites. 
Literature: Lignier (85), Wieland (170, 171). 
Figures: 171, p. 110 and 122. 
The most characteristic feature of this group of fossil 
plants is the occurrence of bisporangiate strobili, which 
are borne on short axillary branches, expanded at their 
top into a receptacle, having a hemisphaerical or more 
or less conical shape. On this receptacle the members 
composing the strobilus occur placed in spiral order. 
Lowermost are the sterile bracts, enclosing entirely the 
central portion, a series of leaflike sporophylls are coming 
