Two Fossil Prothalli . 
3 ii 
Separating the two genera, thus affords some interesting analagies. 
The ti 'ansverse section of the ovule of Araucaria imbricata, shows, 
though in a less marked degree, the same characteristics as the 
fossil. 
In Cycads also a similar state of affairs prevails, the relative 
sizes of prothallus and seed being more comparable with those of 
Lagenostoma than is the case with the Conifers. 
It is not necessary to say anything about the testa, as that 
has been already exhaustively dealt with by Oliver and Scott. In 
this instance, it is perfectly normal. Disorganised remains of 
cupule, recognisable chiefly by the rotted out remains of the mar¬ 
ginal glands, surround the section, but display nothing of special 
interest. 
Enough has been said, perhaps, to render it a fair conclusion, 
that Lagenostoma Loinaxii possessed a prothallus the arrangement 
of whose elements resembles that found in the prothalli of recent 
Gymnosperms, strongly suggesting that it originated in a similar 
manner, by centripetal alveolation. 
The megasporal tissue of Lepidocarpon , commonly well pre¬ 
served, which has an interest in this connection, shows the same 
marginal layer of small cells, and a similar central plexus, but all 
appearance of the most significant feature, the radial arrangement 
in the tissue, is absent. 
Oliver, in describing Stephanospermum? maintains that Lepi¬ 
docarpon has left no seed-bearing progeny, but that present-day 
Gymnosperms have originated from an ancestral type characterised 
by the possession of a pollen chamber. It is not too much to say, 
that this fresh fragment of evidence, in the Gymnospermous affi¬ 
nities of the prothallus of Lagenostoma, tends rather to strengthen 
the above view. 
II— Lycopoo Prothallus (Plate VI). 
This section was discovered by Professor Oliver among a 
number of waste slides belonging to Mr. Lomax, and its locality is 
therefore uncertain, although it is safe to say that it came from the 
Lower Coal Measures, most probably from Dulesgate. It is preserved 
in the common state of coal-hall petrifications, that is to say, by 
mineralization with calcite, and the general state of preservation in 
the surrounding mass seems to have been of a high quality, judging 
1 Loc. cit., in summary. 
