Indledninff 
Introductory. 
Don eiendommelige Gruppe af Arthropoderne, som 
ialmindeliglied gaar under Bensevnelsen Pycnogonider eller 
Havspindler, har lamge hurt til do mindst kjendte Former 
indenfor den nsevnte store Dyrafdeling, og deros systema- 
tiske Stilling har derfor ogsaa lige til det sidste vseret 
meget tvivlsom. I den nyere Tid er imidlertid vort Kjend- 
skab til disse Dyr ble.ven vaesentlig udvidet, idet Gruppen 
er ble.ven gjort til Gjenstand for en meget indgaaende Be- 
handling af forskjellige af vor Tids Forskere. Det er isser 
2 storre Arbeider over disse Dyr. som her maa mevnes, 
nemlig Prof. A. Dohrn’s Bearbeidelse af de i Golfen ved 
Neapel forekommende Former, og Dr. Tloek’s Report over 
det rige under Challenger Expeditionen indsamlede Materiale. 
I begge disse betydelige Arbeider er der, foruden Beskri- 
velser af en hel Del nyo Slmgter og Arter, ogsaa leveret 
meget vigtige Bidrag til disse Dyrs anatomiske Bygning og 
Udviklingshistorie, ligesom ogsaa Forsog til en praicisere 
Inddeling er bleven gjort. Angaaende Havspindlernes For- 
hold til andre Arthropoder, er begge disse Forskere enige 
i, at de ikke, som for ialmindeliglied antaget, kail heutores 
til Arachindernes Classe, ligesaalidt som de kan inordnes 
under Krebsdyrene, men at de maa danno en egen distinct 
Gruppe (Classej inden ArtliropoderneS vidtlpftige Stanime. 
Dette er utvivlsomt rigtigt og vil vistnok blive hamlet at 
alle senere Forskere. hvorved ogsaa mange Misforstaaelser 
ved Tydningen af de forskjellige Dele, der sammensfetter 
Pycnogonidernes Legeme, vil blive undgaaet. 
Det under Nordhavs Expeditionen indsamlede Mate- 
riale af Pycnogonider er meget betydoligt, og da de nor- 
diske Former idethele maa siges endnu at vaere mindre vel 
kjendte, har jeg troet at burde levere udfprlige Beskri- 
velser og Afbildningcr af samtlige Arter. Foruden de un- 
der selve Expeditionen erholdte Arter er for Fuldstsendig- 
heds Skyld medtaget de af mig gjennem en lang Rtekke af 
Aar ved Norges Kyster observerede Former, hvortil endnu 
kommer nogle under Nordenskjolds Expedition 1875 i det 
kariske Hav indsamlede Pycnogonider, som velvilligt har 
vseret mig tilsendt til UndersOgelse at Dr. A. Stuxberg, 
Direktor af Gotheborgs Museum. Det paa deune Maade 
tilveiebragte Materiale er saaledes ikke lidet omfattende og 
vil kunne give et temmelig fuldstamdigt Overblik overPyc- 
nogonidefaunaen i de nordiske og arktiske Have. Det 1 il 
Den norske Nordharsexpedition. G. O. Sars: Pycnogomdea. 
The peculiar group of Arthropods generally passing 
under the name of Pycnogonida, or Sea-Spiders, have long 
been one of the least known forms in that large division 
of animals; and their systematic position has continued up 
to the present day very doubtful. Of late years, however, 
our acquaintance with these animals has been essentially 
extended, the group in question having had exhaustive 
treatment by several naturalists of repute. Two rather 
voluminous productions on Pyc.nogonids crave special notice 
l iere , viz., Professor A. Dohrn’s elaborate investigation of 
the forms occurring in the Bay of Naples, and Dr. I locks 
Report on the rich material from the “Challenger” Expe- 
dition. In each of these important works, we have, be- 
sides descriptions of a number of new genera and species, 
most valuable contributions to the anatomical structure and 
development of the Pycnogonidea, along also with attempts 
in the way of a more precise classification. Concerning 
the relation of the sea-spiders to other Arthropods, both 
authors are agreed, that we cannot, as formerly tor the 
most part assumed, refer these animals to the class Aracli- 
nida, 01 - rather range them under the Crustacea, but that 
they must form a distinct group (class) within the exten- 
sive sub-kingdom of the Arthropoda. This view is unques- 
tionably ’ correct, and will doubtless be taken by all 
subsequent naturalists, which cannot fail moreover to ob- 
viate many misconceptions that tend to arise in determ- 
ining the various parts composing the body of Pycnogo- 
nids. 
The material embracing Pycnogonids from the 
Norwegian North- Atlantic Expedition proved very copious; 
and the Northern forms being on the whole as yet but 
little known, I have seen fit to furnish detailed descrip- 
tions and drawings of all the species. Exclusive of the forms 
met with on the Expedition, regard has been paid to those 
observed by the author during a long series of years on the 
coast of Norway, and also to a few Pycnogonids collected in 
the Kara Sea on Nordenskjold’s Expedition, 1875, kindly 
sent me for examination by Dr. A. Stuxberg, Director of 
the Gothenburg Museum. The material thus brought to- 
gether is, we see, sufficiently comprehensive, affording as 
it does a good general view of the Pycnogonidian fauna 
in the Northern and Arctic Seas. Collation of Dohrn’s 
memoir will show at a glance the character of that fauna 
1 
