Two Fossil Prothalli. 
3°5 
It would appear, then, that the English system is tainted in 
this regard, through the undue stress laid on a single and relatively 
unimportant character; Engler’s system, on the other hand, has 
escaped this objection, and reflects the genealogy which we have 
attempted to portray. At the same time we have found reason for 
supporting the place assigned in the older system to Cucurbitaceae. 
We shall, however, have some general remarks to make upon 
certain principles of classification in our next, the closing chapter. 
[7 'o be concluded ]. 
TWO FOSSIL PROTHALLI FROM THE LOWER 
COAL MEASURES. 
By R. C. McLean, B.Sc. (Lond.), 
Botany School, Cambridge. 
[Plates V and VI and Two Text-Figs.] 
ri^HERE are but few fossil prothalli preserved to us from the 
Palaeozoic ages, and even among the few that are known 
a good state of preservation is decidedly rare. This rarity may be 
due partly to minute size, which hinders their recognition in the 
matrix, and partly also to their own unsubstantial nature in the first 
instance. 
The two examples here to be described, belong respectively, to 
the Pteridospermic seed, Lagenostoma Lomaxii (Williamson), and 
to the megaspore of a species of Lycopod (possibly Bothro¬ 
dendron), which it has not been possible to relate with certainty 
to any parent plant. There is a close resemblance apparent between 
the figures given by Mr. D. M. S. Watson of the megaspores in 
Bothrodendron mundnm, and the present specimen. 1 
Both specimens are in the hands of Professor F. W. Oliver, 
F.R.S., to whom 1 am indebted for their use. Taking them in 
detail, the Lagenostoma prothallus will be dealt with first. 
’ Since the above was written Mr. Watson has certified the reality of 
this resemblance. The spore is therefore to be regarded as belonging 
to Bothrodendron. 
