593 
On the Ribbing of the Seeds of Ginkgo . 
angle between the lower two ridges of Fig. 2 lying also between 135 0 and 160 0 . 
Even in seeds like those resembling our Fig. 8 three different forms might 
be distinguished, although the differences were again not of much importance. 
A number of them (ten out of nineteen) agreed with the figure, in which we 
see one face occupying one-half of the stone, the two other the remainder. 
In seven specimens, however, the two large sides were of equal size, and in 
the last case (two seeds) the third rib was not entirely developed, as it died 
out between the base and the apex. 
Besides these two- and three-angled forms there were a few four-sided 
ones, only five in number, four of which are represented in our Figs. 10-13. 
The seeds represented in Figs. 10 and 11 might be regarded as normal 
two-angled ones (like our Fig. 1) with two accessory ridges on one of 
the faces. The stone of Fig. 12, on the other hand, looked much more like 
a nearly regular three-sided one, with a fourth rib on its largest face. 
Fig. 13 was the finest four-angled seed of all, but it was not regular in 
shape ; two of the faces (the lower and the left-hand ones in the figure) were 
equally large, occupying each one-fourth of the circumference, but in the two 
others one face was larger and the other smaller than that fourth part. 
The fifth and last stone, not represented, resembled both Fig. 10 and 
Fig. 6, the difference from the latter consisting only in the presence of 
a fourth ridge on the smallest of its three sides. 
The number of the seeds available was evidently too small to permit 
any general conclusion, but, on the other hand, as it was large enough 
to give at least an idea as to their frequency, we append the following 
table: 
Number of 
Number of 
Number of seeds 
ribs. 
seeds. 
of each kind. 
2 
47 
47 (Fig. 1) 
3 
65 
6 (Fig. 2) 
2 (Fig. 3) 
5 (Fig. 4) 
9 (Fig. 5) 
8 (Fig. 6) 
4 
5 
Total 117 
i 
3 (Fig. 7) 
19 (Fig. 8) 
(13 (Fig. 9) 
f 2 (Fig- 10) 
I (Fig. 11) 
| 1 (Fig. 12) 
l 1 (Fig- 13) 
Thus the two-sided seeds did not dominate at all, as there were only 
40 per cent, of them; there were even more three-angled ones, i. e. no less 
than 55 per cent., so that it is hardly possible to conclude anything about 
their ordinary feature. We can therefore agree entirely with the conclusion 
of Oliver and Salisbury ( 9 , p. 44), who say : ‘ The facts seem to indicate 
that, whilst the terms “ radiospermic ” and “ platyspermic ” have a definite 
