Lepidocarpon lomaxi Scott. There is an inner layer of 
thin-walled elongated cells. The megaspore grows to 
great size and is the single functional member of a tetrad 
of four spores. In one of her specimens Miss Reed rec- 
ognized three aborting megaspores, and shows conclusive- 
ly that they did not disintegrate immediately following 
inception, but that there was a relatively short growth 
period for all four megaspores, the proximal spore soon 
gaining ascendency over the others. In time, the larger 
of the spores seems to fill the whole cavity. Often, the 
megaspore membrane is collapsed. Miss Reed notes that 
never in her experience has she found gametophytic tis- 
sue; fragments of tissue which occur occasionally inside 
the membrane are intruded. She has developed this idea 
further and argues that the conventional opinion that 
Selaginella foreshadows seed structure is erroneous. She 
concludes that Lepedocarpon is a sporangium containing 
a living dependent gametophyte. 
Several years ago Schopf (11) described impressions 
of Lepidocarpon mazonense from Mazon Creek in north- 
ern Illinois. It appears that this interesting species is 
very abundant, for he was able to collect forty specimens 
in a few visits to the locality. Prior to this discovery 
little was known of the variability or the gross form of the 
sporangium and its associated sporophyll in Lepidocar- 
pon. In amore recent contribution Schopf (in Janssen 
(5), pp. 89-45) added still more information on these 
structures. He described Lepidocarpon corticosum (Les- 
quereux) Schopf as ‘‘a seed structure 11 mm. long and 
7.5 mm. tall’? borne upon a sporophyll of medium size, 
with the integumentary structures of the seed attached 
along a ventral extension of the pedicel enclosing the seed. 
‘The proximal end of the pedicel merges with a ‘‘splinter’’ 
of the former cone axis. The functional or seed-megaspore 
is 7 mm. long and 3.75 mm. broad; the broader end of 
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