Affinities of the Palaeozoic Seeds of the Conostoma Group. 33 
The pollen-grains found in the plinth have 80 ^ x 65 /x as average 
dimensions, as compared with 75 m x 63 /x in C. oblongum , and 85/XX75/X 
in ( 7 . anglo-germanicum. 
The Integument. The micropylar tube, funnel, and plinth jacket 
present in specimens B. 230, C. 2 and 6, 1 were doubtless integumental in 
origin. The tube reached a considerable length and was named the 
* entonnoir ’ by Renault ; in specimen B. 230, C. 6, 2 it contained grains of 
pollen fossilized eh rotite to the lagenostome and plinth cavity. 
A conspicuous feature of the integument, especially towards the apex 
of the seed, was the presence of ‘ un tissu lacuneux forme de grandes 
cellules disposees en lames paralleles ’. 3 This tissue, conjectured by Renault 
to function as a float giving buoyancy to the seeds in water, resembles in 
the closest way the ‘blow-off’ tissue found in Conostoma , and we see no 
reason to doubt their essential identity. 4 
A great peculiarity of the seeds of Gnetopsis was the tuft of apical 
plumes inserted around the micropyle. Of these structures no trace is 
shown by Conostoma , so that unless they were caducous in the latter, 
their absence must be regarded as an important point of distinction 
between the two seeds. In view of the slight flattening detected in the 
body of Conostoma oblongum it is of interest to note that in Gnetopsis the 
symmetry was likewise modified in the direction of platyspermy ; 5 whilst 
in C. oblongum , however, the whole of the six vascular bundles are accounted 
for, in Gnetopsis there are only four, those corresponding with the positions 
we suppose to represent the two major angles being absent. Gnetopsis 
thus appears to combine in itself the peculiarities of both our seeds, in 
showing the flattening of C. oblongum , with the disappearance of some of 
the bundles as in C. anglo-germanicum. 
Another point in which Gnetopsis perhaps differed from our seeds was 
in the relatively slight development of a ‘ tent-pole’. As practically every 
specimen of Gnetopsis contained a prothallus these seeds should be of the 
right age, as judged by Conostoma , to show the £ tent-pole ’ had it reached 
any degree of prominence. 
Turning to the cupule which formed the common enclosure of from 
two to four seeds in Gnetopsis , we have, as yet, no parallel in Conostoma , 
where the seeds are only known as detached objects. 6 
Having regard then to the various points cited, viz. the lagenostome, 
plinth, micropyle and plinth jacket, ‘ blow-off,’ symmetry and distribution 
of vascular strands, we think the case for the close association of Gnetopsis 
with, or even its inclusion in, the Conostoma group a very strong one. 
1 Renault : loc. cit., PI. XX, Figs. 2, 3, 4. 2 Renault : loc. cit., PI. XXI, Fig. 3, o. 
8 Renault : loc. cit., PI. XX, Figs. 2 and 3, /. 
4 Cf. our PI. Ill, Fig. 29, and Renault, loc. cit., PI. XXI, Fig. 3. 
6 Cf. our Text-fig. 11, p. 34, and Renault, loc. cit., PI. XXI, Fig. 6. 
6 See however pp. 15 and 16. 
D 
