108 PROCEEDINGS OF THE NATIONAL MUSEUM

wastakenonthe surface close

by

the spotwherethetwocoldwater specieswere brought up fromthedeeper waters, the surfacetempera- tures

bemg

77°-80°, thatat245fathoms33.1°. Haeckel's recordof Aeginopsis unfortunately gives neither the date, whether winter or summer, nor the exact locaUty.

And

both of these are of im- portance,because in

summer

the surface temperatures of the Sea ofJapan rangefrom about60° (northern end) to about80° (Korea Channel); while in winter the surface waters of its northern half,

betweenHoklcaido and the Siberiancoast, are cooledto45°orless.

In the portion of the Eastern Sea south of the Straits of Korea traversed

by

the Albatross, the hauls brought to light an abundant harvest of medusae, the species taken near the Goto Islands,off

Kagoshima

Gulf, andoffKyushiuIsland being

—

1. Medusae.

Turritopsisnutricula.

Aequoreapensile.

Olindioidesfonnosa.

Aglmirahemistoma.

Rhopalonemavelatum.

Colobonematypicum.

Crossotaalba.

Liriopetetraphylla.

Rosaceaplicata.

Neclodromareticulata.

HippopodiusMppopus.

Vogtia pentacantha.

Ahylopsistetragona.

Bassiabassensis.

Clausophyesgalatea.

Galeolariaaustralis.

Galeolaria monoica.

Chuniphyesmultidentata.

Geryoniaproboscidalis.

Sobnundellabitentaculata.

Periphylla hyacinthina.

Nausiilioepunctata.

Atollawyvillei.

Pelagia panopyra.

Sanderia malayensis.

Parumbrosapolylobata.

2. SiPHONOPHORAE.

Diphyestruncata.

Diphyesappendiculata.

Diphyescontorta.

Diphyesspiralis.

Diphyopsisdispar.

Diphyopsismitra.

Diphyopsis chamissonis.

Agalmaolceni.

Archangelopsistypica.

Parpitapacifica.

The

list isessentially tropical, as might have been expectedfrom the surface temperatures (83°-85°) attheseason the collection

was

gathered, all the surface

medusae

being

known

from the tropical partsofthePacificorIndian Oceans, except Turritopsis nutriculata, Olindioides,and Parumhrosapolyhata, thelasttwo

known

onlyfrom Japan. Allthe siphonophores,except Vogtia pentacantha,are

known

fromthetropical Pacific,orfromtheMalaysianregion,whilemostof

them

are characteristic of the

warmer

regions of all three great oceans.

During the

summer

months,

when

the southeastern coasts of Japan are bathed

by

the

warm Kuro

Shiro current, the tropical holoplanktonic coelenterate fauna extends northward along the coast of Nipon,at least as far asSuruga and Sagami Bays, where

NO.1946. PACIFIC

MEDUSAE AND SIPHONOPHORAE—BIGELOW. 109

thecombinedrecordsofKishinoiiye(1902, 1910),

Maas

(1909),Doflein (1906),andtheFisheriessteamerAlbatross,haverevealed the following tropical species: Cytaeis vulgaris, Clavula papua, Prohoscydactyla omata, PTiialidium pacificum, P. discoida, Aequoreapensile, Liriope tetraphylla, Geryonia prohoscidalis, Rhopalonema velatum, Aglaura Tiemistoma, Solmundella, Cunina peregrina, CTianjhdea rastonii, Pelagia panopyra, Sanderia malayensis, Dactylometrapacijica,Thysano- stomatliysanura and Mastigias papua, with the following siphono- phores, Ahylopsis tetragona, DipJiyes appendiculata, Dipliyopsis dispar, Dipliyopsis chamissoms, Forslcalea, Pliysalia, Porpita, and Velella; all of

them

being widely distributed inthetropical parts oftheIndo-Pacific.

This list suggests that thepelagiccoelenteratefaunaofthe south- eastcoastofJapanin

summer

isoverwhelminglytropical; butsucha conclusioniscorrectonlyforitsholoplanktonic constituent

—

^thatis,

forthe inhabitants ^of the

warm

waters of the

Kuro

Shiro, and for certain scyphomedusae.

With

the leptolineformsquite a different state of affairs is to beseen, because thelist does not include any of the leptoline hydromedusae which are the most characteristic

members

^of the

medusa

fauna of the Phihppines, the Malaysian region, or ofthe Maldives and tropical Pacific,such asBougainvillea fulva, Laodicefijiana, Tiaropsisrosea,

PMalucium

mbenglia, Irenopsis hexanemalis,

Eutima

levulca,Octocanna polynema,Gonionemussuvaen-

sis, orthe genera EupTiysora, PJiortis, or Olindias.

A

fulllistofthe Phihppine, Malaysian, and tropical

West

American hydromedusae, and their distribution, ^will be found in

my

report on the Albatross Philippinemedusae.

In Japanese waters the place^of Olindias is taken

by

Olindioides, ofthe tropicalGonionemus suvaensis,

by

G. vertens, var. depressum, which is aclose

aUy

ofthe Gonionemusofthe cold waters ofPuget Sound, and of

New

England. Other Japanese leptoline forms recorded

by

Kishinouye(1910)and

by Maas

(1909),suchasNemopsis

dofleini, Willia pacijica, Spirocodon saltatrix, are peculiar to Japan, so far as

we know

yet.

The

absenceofthetypically tropical leptoline species, which are so

common among

the Philippines, is probably not an accidental failure in collection, but is an actual condition, duetothelow temperatureofthewatersofftheeastcoastofJapan in winter, which they, or their hydroids, can not survive.

But

in the case of the holoplanktonic species, this bar is operative only in winter, for they are brought to Japan in

summer by

the

Kuro

Shiro,

when

the latter

^reads

toward thenorth.

Unfortunately

we

have almost no data on the

medusa

fauna of the east coast of Nipon, north of

Yokohama

Bay; indeed I have not been able to find a single definite record; but

we

can safely assumethat beforeTsugaruStraitisreached thetropicalcontingent

110 PB0CEEDIN08 OF THE NATIONAL MUSEUM.

vol.44.

of the

medusa

and siphonophore faunaswings

awaj

from thecoast, with the easterlytrend of the

Kuro

Shiro current,because thefew species previously

known

from the east coast of Hokkaido, and those found there

by

the Albatross, that is, Sarsia japonica, PtycJiogena lactea, AglantJia digitale, Haliclystus auricula, Aurelia aurita,Aurelialimhata,andDipliyesarctica,are ofadistinctlynorth- erncast.

In

summer

the

warm Kuro

Shiro water, with its characteristic fauna,isperiodicallydriven outfromthe shoreoffTsurugaGulf,

by

northwestwinds, anditsplacetaken

by much

colderwater (Doflein, 1908); and the few available winter records, for example, RatKkea hlumenbachii and PhacellopJiora amhigua fromMisaki (Kishinouye),

show

that

some

northern species reach the coasts of Nipon atthat season; whether anyof

them

do so in

summer

isnot yet known.

An

interesting parallel

may

be

drawn

betweenthe pelagic coelen- terate fauna of the northeastern coasts of Asia and that of the northeast coast of the United States. It has, ofcourse, beenlong recognized that theeast coast ofJapan and the southern shores of

New

England sharecertain striking oceanicphenomena, both being bathed in winter

by

cold, almost Arctic waters ^of northern origin, whichin

summer

are periodically displaced

by

the northerly swing of a very

warm

current, the

Kuro

Shiro in the Pacific, the GuLf Stream in the Atlantic.

On

the Japanese coast the

warm

stream holds almost continuous

sway

in

summer;

but on the south coast of

New

England its full effect is felt only occasionally, though it

tempers the surface waters to a

marked

degree throughout the

warm

months. Off the coast of Nipon, in the region of

Sagami

and SurugaGulf theannual rangeoftemperatureisfrom about50°

to about 80°; off Narragansett Bay, in

New

England, from about 38° (it occasionally freezes in the bay)to about 76°; andofcourse evengreaterextremes andvarious anomaliesareobservedin partially enclosed waters.

To

both of these regions the

warm

current brings an abundant tropical oceanic pelagic fauna in

summer;

but this deserts

New

England, and probably Japan, in autumn,

when

the

warm

waters to which it belongs recede.

And

in neither region is the leptoline

medusa

fauna tropical; thus there are very few leptoline species

common

to Narragansett

Bay

and to the

West

Indies, though the formerreceives a

number

ofcharacteristic tropicaloceanic

medusae

every

summer;

and the

same

is true of Japan; nor indeed would

we

expect to find litoraltropical species takingpermanent foothold in regionswhere they would have tosurvive boreal temperatures at

some

stageofdevelopment.

In

New

Englandtropicalmedusae seldompenetrate northofMas- sachusettsBay,beyond whichpoint, insummer,

we

findborealspecies such as Melicertum campanula, Staurophora mertensii, Catableraa

NO. 1946. PACIFIC

MEDUSAE AND 8IPH0N0PH0RAE—BIGEL0W.

_Ill

vesicaria, which appear only in wintersouth of Cape Cod; and in Japan^theTsugaruStrait

marks

asimilar division.

But

bothinthe AtlanticandinthePacifictherearerecordsoftheoccurrenceoftrop- icalcoelenteratesfromfarnorthof theirusualrange,suchasPhysalia inthe

Bay

ofFundy,PelagiainBeringSea.

In the cold season the processof dispersalis reversed, the

warm-

water species receding, the cold-water ones advancing toward the south.

We

^do not

know

just

how

far southward boreal medusae extend along the coasts of theUnited States inwinter, but several appear regularlyat that seasonat

Woods

Hole and in Narragansett Bay,

and

Ihavemyself seen the watersofPamlico

Sound

(onlyafew miles north of

Cape

Hatteras) crowded with thedark red northern Cyanea,inJanuary,afterprolonged northeast storms. InJapan, as pointed out above, boreal speciesappearin Sagami

Bay

during the cold season, and it is probable that they advance even farther southward.