British Coal Measures . 
87 
the valves ? It seems to me to be much more likely that we are dealing 
here with the true external surface of a radiospermic seed. In a very large 
number of examples no trace of any fleshy sarcotesta is to be seen, and 
therefore this is presumably not a forma j 3 cast. My view is that it is the 
external surface of a seed, the integument of which when ripe opened by 
three valves exposing the nucellus at the apex of the seed ; that the 
foramen represents the point of attachment of the stalk, and that the cast 
seen within is a cast of the nucellus. I therefore propose to transfer this 
species to the Radiosperms, as a member of a new genus Schizospermum , 
namely S. Noeggerathi (Sternb.). The possession of three longitudinal ridges 
is common to several other Radiosperms, as will be shown here, and the 
foramen and inner cast are also seen in some of these. Further, in a unique 
but obscure specimen, at present referred to the new genus Radiospermum 
as R. problematicum (PL VII, Fig. 37), there is also evidence of splitting at 
one extremity of the seed. At present, however, it is not known whether 
this was a natural feature or not. 
Radiospermum ovatum (L. and H.) (PI. VII, Fig. 32). There is a large 
and very rare seed in the Middle Coal Measures of Coalbrookdale and 
Yorkshire, which was first figured by Lindley and Hutton 1 as Trigonocarpum 
ovatum , and by Morris 2 as Carpolithes zamioides . The cast is cylindrical ; 
there are three well-marked longitudinal ridges, as in many other radio- 
spermic seeds, and a foramen occurs at the base, disclosing an inner cast. 
It differs from Schizospermum Noeggerathi in the fact that the integument 
of the seed does not separate into three valves, and also in size and shape. 
This also I am inclined to regard provisionally as the external surface of 
a radiospermic seed, and not as a cast of the seed cavity of a y form of 
Trigonocarpus . It seems to me to fall within the new genus Radiospermum 
as defined below (p. 92). 
Platyspermum , gen. nova., and Rhabdocarpus , Berg. 
This completes the list of British Coal Measure plants which have 
been referred to the genus Trigonocarpus. We now turn to the platy- 
spermic seeds, and especially to those hitherto referred to the genus Rhabdo- 
carpus. This name appears to be used in a somewhat loose sense at the 
present time. 3 In my opinion it should be reserved for unsymmetrical 
seeds, similar to Rhabdocarpus timicatus , Berger, 4 as the type of the genus, 
and R. subtunicatus , Zeiller. 5 These seeds are Platysperms, with a large 
1 Lindley and Hutton (’31), vol. ii, PI. CXLII a. 
2 Morris (’40), p. 489, PL XXXVIII, Fig. 4. 
3 Berger, the founder of the genus, himself included several different types under this name. 
His paper is, however, merely a student’s thesis for a degree, and it is doubtful whether such 
dissertations should be recognized. 4 Berger (’48), p. 20, PI. I, Fig. 8 (right side). 
5 Zeiller (’92), p. 93, PI. XV, Fig. 11 ; the R. tunicatus of Grand’ Eury (’77), pp. 206, 313, 
PI. XV, Fig. 12 ; and Renault (’90), p. 638, PL LXXII, Fig. 19. 
