168 
Simmons, Kemarks about tke Relations of tke Tloras etc. 
referring of a species to one of tlie gronps or anotker is solely 
based upon kow far soutkwards or nortkwards tke writer tkinks 
it to be found, tkere raust be an everlasting interckange of 
species between tke groups, especially tke nortkatlantic and tke 
subarctic series, as is easily seen by comparing tke lists in tke 
above mentioned treatises and tkose of Rosen vinge (44) and 
Börgesen (8). Comparisons of percentage of species, referred 
to tkose series, suck as are to be found in tke papers quoted. 
can not be of tke skgktest interest, as it is seifevident tkat, if 
species tkat liave tkeir distribution ckiefly far nortkwards are 
called arctic, tkose witk a somewkat more sontkerly area, sub¬ 
arctic, a. s. o., a coastline furtker to tke nortk will always skow 
a greater percentage of „arctic“ species, tkan one fartlier soutk- 
wards, and vice versa — if not some special circumstance plays 
in. Börgesen (8) for instance devotes several pages to suck 
examinations and comparisons, as tke „result“ of wkick it appears, 
tkat in tke flora of tke Raeroes (lying in tke nortkern Atlantic) 
tkere is a very great percentage of „nortkatlantic species“. 
Tke fable (VI) skows, tkat most of tke arctic algae are also 
found in some parts of tke Atlantic (87 per et,). Of tliese 
again 64 (40 per et. of total number) are also spread to tke 
nortkern part of tke Pacific. Among tkese we will find most of 
tke species, wkick kave a wide distribution in tke arctic seas 
and also a few species witk a very wide ränge, suck as are 
found again in tke soutkern temperate region or even in tke 
antarctic, and also suck as are spread even to tke warmer 
parts of tke oceans. Tke species common to tke arctic flora 
and tkat of tke Pacific are muck fewer tkan tkose, wkick tke 
former kas in common witk tke atlantic one, 70 species (44 per 
ct.). Of tkese 6 only are not found even in-tke nortkern 
Atlantic, naraely Maria dolichorachis , * Laminaria cuneifolia. 
*Rhodymenia pertusa, Bhodomela larix, Ptilota asplenioides , *DiIsea 
Integra. Hereto comes furtker Laminaria solidungula if tkat 
species really grows in tke Pacific and not only young specimens 
of Cymathere triplicata are taken for it as Setc-kell (49, p. 260) 
tkinks. Of tke six species tkree, marked witk *are found also in 
parts of tke Polar Sea lying nortk of tke Atlantic. Kj eil man 
(30, p. 53) sees in tke existence of suck a distribution a proof 
for tke assumption of a centre of dispersion in tke Polar Sea 
itself. I will not deny, tkat so may kave been, only I tkink 
tke continuity of tke evolution witkin tke Polar Sea very 
doubtful. Tkere also are atlantic species tkat reacli far into 
tke arctic area, even nortk of Asia and America, Suck are: 
Chantransia efflorescens, Turnerelia Pennyi, PJwdocJtorton 
penicilli forme, Lithothamnion foecundum; more dubious are 
Laminaria digitata , L. longicruris , PJwdocJwrton sparsum , 
Cruoriella Pubyii. I do not liowever tkink tkere is too muck 
stress to be laid on tkis fact. Tke tkree pacific-arctic species, 
wkick only go a sliort way into tke arctic sea front Bering 
Strait, viz. Maria dolichorachis, Bhodomela larix, Ptilota asple- 
