140 BOTANICAL GAZETTE [OCTOBER 
shown in this figure, for example, the Lagenostomales (a—d), the 
Trigonocarpeae (a'~c'), and the microsporangia (I, II, III, IV) 
illustrate the fact that at least two lines of progression can be 
traced in Pteridosperm seeds, each with members suggesting an 
early descent from a sporange with paired loculi. These paired 
loculi occur in both Heterotheca and Crossotheca. A tendency to 
simplification is seen in all three groups, Conostoma among the 
Lagenostomales and Telangiwm among the microsporangia showing 
a halving of the number of parts. Again an example of lobing 
occurs in one seed of the Lagenostomales (Physostoma, text fig. 8, 
d), and in one type of microsporangium (Codonotheca, text 
fig. 8, IV). 
Summary and conclusions 
1. Among the remains of Helerangium Grievii (vegetative organs 
and seed) in the calcified deposits of plants occurring at Pettycur, 
Fifeshire, have been found large numbers of a new type of micro- 
sporange for which the form genus Heterotheca has been constructed. 
2. Its mechanical structure is similar to that of the petioles of 
Heterangium, and, although so far found detached, it is attributed 
to Heterangium on the same grounds as are the vegetative organs, 
that is, the presence of vertical and horizontal sclerotic plates. 
3. Its spore bearing tissue is distributed in sixteen series of 
loculi, of which twelve are peripheral and four central. The 
vascular bundles are similar to those of the seed, and near the apex 
each is nearly surrounded by a pair of loculi as in the canopy of 
the seed. 
4. The structure throughout is strongly confirmatory of the 
homology of the seed and synangium, and is regarded as supplying 
ample proof of the synangial origin of the seed. 
5. In this investigation we seem to stand upon the threshold of 
the origin of at least one group of the Spermatophyta, and the 
conclusions reached cannot fail to have their influence on the study 
of other groups. 
RoyaL Hottoway CoLLecE 
ENGLEFIELD GREEN 
SuRREY, ENGLAND 
