PHILOSOPHICAL TB AN S ACTION S. 
I. On the Organization of the Fossil Plants of the Coal-measures. — Part VII. 
Myelopteris, Psaronius, and Kaloxylon. By W. C. Williamson, F.B.S., Professor 
of Natural History in the Owens College , Manchester. 
Received June 3, — Read June 10, 1875. 
The existence or non-existence of the remains of Palms in the Carboniferous strata has 
long been a debated geological question. Accepting the determinations of Corda as 
announced in his ‘Flora der Vorwelt,’ many geologists admitted these true endogens 
into their lists of Carboniferous plants. Cotta had figured, in his ‘ Dendrolithen,’ three 
very anomalous stems, under the names of Medullosa porosa, stellata , and elegans. 
Corda, in his ‘ Flora der Vorwelt,’ subsequently figured two stems from Carboniferous 
strata obviously allied to one, at least, of Cotta’s types, under the names of Palmacites 
carhonigerus and P. leptoxylon , which he placed in the class of Palms. Cotta’s figures 
of Medullosa elegans are very misleading, though they are not very unlike the specimens 
which he probably described. Some specimens now in the British Museum which came 
direct from Cotta, and for having my attention drawn to which I am indebted to my 
friend Mr. Carruthers, exhibit a remarkable areolation when cut transversely. This 
areolation Cotta has not only copied but exaggerated; hence the peculiar aspects 
of his figures 1 & 8 of his Medullosa elegans ; it certainly is not a constant and 
normal feature, but the result of some change produced subsequent to the life of 
the plant — most probably a consequence of partial desiccation of the stem. Cotta’s 
drawings of the cortical layer also are very misleading ; hence it is very unsafe to accept 
his delineations apart from the study of his specimens, some of which, I fear, are no 
longer to be found. The consequence is that two of his species, M. stellata and M. 
porosa, remain too obscure to be relied upon without further evidence than Cotta has 
handed down to us. 
The first to throw doubt upon the Monocotyledonous character of these plants was 
M. Brongniart in his ‘Tableau des genres de Vegetaux fossiles,’ published in 1849, 
extracted from the ‘ Dictionnaire Universel d’Histoire Naturelle.’ He identified Cotta’s 
Medullosa elegans with some important plants not uncommon in the Carboniferous beds 
MDCCCLXXVI. ' B 
