132 BOTANICAL GAZETTE [OCTOBER 
Thus, as the absolute parallel between seed and synangium could 
not then be demonstrated, there were critics who preferred to lay 
stress on the possibility of the seed having acquired its character- 
istic structure independently of its ancestral condition, rather than 
by a transformation of structures already present. The inner 
integument, as well as the outer or indusial envelope, was attrib- 
uted to foliar upgrowths around the nucellus, which alone was 
regarded as the representative of the ancestral sporange. The 
views of such critics are summed up by OLIVER (13) in his account 
of Physostoma elegans in the following words: 
oe oe sug d though ne Seale tenable, presupposes in the ancestor 
h f a synangium, in which the peripheral : 
members were ranged “symmetrically around a central sporangium, and in 
which they persist as a sterilized envelope to form the seed coat. 
Having at that time already secured several specimens which 
indicated the existence of a synangium with central loculi sur- 
rounded by peripheral ones, the writer took an early opportunity 
of collecting some more of the Pettycur deposits in which these 
interesting specimens occurred. By 1911, several hundred sections 
had been cut from two of the blocks collected the previous year. 
These blocks contained much Heterangium Grievii material, and 
yielded the large number of specimens now available of the new 
synangium. Owing to the care with which the stones were cut, 
many of the synangia, although scarcely 4 mm. in length and 2 mm. 
in width, are represented by series of three or four sections in the 
transverse plane or two in the longitudinal plane. The average 
thickness of the stone involved in the section cutting was 0.8 mm. 
As already stated, the series of transverse sections CN .307- 
17-19, CN .343.10-13, and CN.412.30-31, although cut from 
different blocks, demonstrate clearly with many others that a 
synangium was present in these older rocks, associated with and 
showing the characteristic cortical structures of Heterangium 
Grievit, a synangium in which central loculi, as well as the more 
commonly occurring peripheral, occur. It is also interesting that 
even in the microsporangial apparatus an unusual amount of 
vegetative tissue obtained was also clearly shown for the first 
time. The publication of the details of the structure of Sphaero- 
