180 
Simmons, Remarks about tke Relations of tke Floras etc. 
For convenience I kave used different signs to mark tke 
distribution of families (—) and genera (X). 
Before going into detail witk tke conclusions tkat can be 
drawn from tke above table, it will be useful to snmmarize 
tke distribution of tke families as follows: 
Table IX. 
Arctic 
Not arctic 
o 
r- 
Atlantic 
, 
.Sc 
S "o 
V 5 
Zß 
c3 
O 
m 
m 
o 
i—i 
6 6 c® 
O CD 
jS c3 ^7 - 
kl 
Atlantic 
Atlantic 
pacific and 
Southern 
CO 
c3 
C 
m 
CO 
Q 
c2 | 
© 
w 
Phaeophyceae 
Rhodophyceae 
1 
1 
10 
14 
1 
4 
1 
1 
2 
4 
1 
19 
21 
Togetker 
1 
1 
24 
1 
5 
1 
6 
1 
40 
Out of 40 (marine) families 27 are represented in tke Arctic 
Sea and of tkese again 24 kave a wide distribution in most 
parts of tke oceans. As tke families, mostly at least, represent 
very old types it is natural tkat tkey skould kave spread so 
far. About tke age of tke few families, tkat kave a more 
narrow area, it is kardly possible to kave any opinion, but for 
tke tkree arctic ones it seems most probable tkat tke following 
preglacial liomesteads must be supposed: for Lithodermataceae 
tke Polar Sea, for Tilopteridaceae tke sea soutk of tke tertiary 
landbridge. Tkat tke Didyosiphonacea% kave been represented 
in tke tertiary Polar Sea can kardly be doubted, but on tke 
otker kand tkey kave anotker area of distribution in tke soutk, 
prob ab ly also old, as tkey are represented tkere not only by 
a Didyosiphon (?) but also by an endemic genus Scytothamnus . 
Of tke 13 families not present in tke arctic regions 6 kave 
a wide distribution, and 5 otkers only are represented in tke 
atlantic area. Tke latter are all suck as only kave a very 
limited number of species. Probably tkese lead tkeir origin 
from tke tertiary-atlantic ilora. One family, Gloiosiphoniaceae , 
lias a distribution somewkat similar to tkat of tlie Didyo- 
siphonaceae and may perliaps kave been present in tke tertiary 
Polar Sea, altliougk it is now entirely wanting in tkose waters. 
As can be seen of tke table IX, tkere is only a single family, 
Acrotylaceae , tkat is entirely absent from tke Atlantic. Perliaps 
tkis ocean really is ricker in different algae tlian otker seas, 
most probably liowever tkis apparent great er abundance of 
forms is due in a great measure to tke better exploration of 
tkose waters. Future researckes perliaps will make it necessary 
to take anotker view upon tke kistory of some of tke above- 
