304 
Notes . 
Furthermore, each principal ridge is characterized by a longitudinal crack in its 
plane of symmetry, proceeding from the furrow on the interior surface of the sclerotesta. 
Hence a close general agreement obtains between the two seeds {Trigonocarpus 
Parkinsoni and P olylophospermum stephanense') — ( i ) in the differentiation of the ridges ; 
(2) in the presence of a sarcotestal vascular system ; (3) in the correlation with the 
principal and secondary ridges of radial cracks and vascular bundles, respectively. 
Under these circumstances it is of interest that a seed should have come to light 
(T. Oliveri), showing transitional characters between the two genera. 
Fig. 1. Polylophospermum stephanense. 
A, transverse section of seed showing the position of the vascular bundles of the sarcotesta and 
their relation to the ridges, n. nucellus ; mg. megaspore membrane ; sar. sarcotesta ; scl. sclerotesta ; 
v.b. vascular bundles, x 8. 
B, longitudinal section of the chalazal end of a seed. v.b. vascular bundle, x 4. 
Before closing this note there is one point I would raise before it is too late. 
In Pt. I of their paper 1 the authors show a tendency to adopt the term Stephano- 
spermeae as the group-name for the seeds showing a general agreement in structure 
with Trigonocarpus. My plea is that Stephanospermeae be abandoned in favour of the 
much more appropriate Trigonocarpeae. The only justification for the term Stephano- 
spermeae is that at the time it was proposed it embodied the name of the seed the 
anatomy of which had been investigated in rather more detail, perhaps, than was the 
case with any other member of the group. To-day that qualification is no longer 
valid. Moreover, Trigonocarpus is the Coal-measure seed par excellence , and has been 
the subject of numerous memoirs and references scattered over the palaeo-botanical 
literature of nearly a century. It is widely distributed, and is known under both 
forms of preservation ; whilst the casts and petrifactions have been correlated in detail. 
Hence on every ground Trigonocarpus has pre-eminent claims to give its name to the 
group. 
F. W. OLIVER. 
1 Scott and Maslen, loc. cit. 
