4 
De nedenfor optbrte nye Arter har af mig tidligere 
vseret kortelig charaeteriserede i 3 forelobige, i Archiv f. 
Mathem. og Nattfrvidenskab i ml forte Afhandlinger. Nogle 
af disse her forste Gang omtalte Arter or til dels af senere 
Forskere bleven gjenfundne og nedere beskrevne og afbil- 
dede, dog ikke saa udforligt, at jeg finder on fomyet Be- 
skrivelse unodvendig. 
De af a; Id re Autores givne Beskrivelser og Figurcr 
af Pycnogonider er ialmindelighed ydei’st ufuldkomne, og 
dot or derfor ogsaa forbunden mod sferdeles stor Vanske- 
lighed at jdentificere de af deni opstillede Arter, ja i en- 
kelte Tilfselde ondog Iigefrem ugjorligt. Dog tror jeg, at 
adskillige af de nyere Forskere har her ikke gjort sig den 
tilstraskkolige Umage og forkastet som ubrngelige et storre 
Antal af seldre Beskrivelser end strengt taget nqdvendigt. 
Navnlig synes dette at have vseret Tilfieldet med Dohra, 
hvad der klarlig nok fremgaar af dot eiendommelige Fac- 
tum, at alle de af ham opforte Arter fra Golfen ved 
Neapel beskrives som nye, alene mod Undtagelse af en 
eneste, Rhynchothorax mediterraneus, og det uagtet ikke 
taa middelhavske Former, tidligere har vseret beskrevne, 
enkelte til og med fra samrne Lokalitet. At flere af de i 
Dohrn’s Vserk opforte nye Arter i Yirkelighedon er iden- 
tiske med tidligere beskrevne, anser jeg for ganske utvivl 
somt, og jog har ogsaa Grand til at antage, at enkelte af 
de nye Slsegter vil vise sig uholdbare som saadanne. 
For de nordiske Arters Vcdkommende har jeg saa sam- 
vittighedsfuldt som miiligt confereret med seldre Beskri- 
velser og har ogsaa seet mig istand til at hsevde i sin Bet 
igjen enkelte forglemte eller negligerede, af tidligere For- 
skere (f. Ex. Goodsir) opstillede Arter. 
Den i memerendo Vserk givne Fremstilling er af 
rent descriptiv Art og har vmsentlig kun til Formaal, 'ved 
en indgaaende sammenlignende Undersogelse af de mere 
almindelige Bygningsforhold at faa noiere udredet de til 
den nordiske Pycnogonidefauna hprende Slsegter og Arter. 
Hvad den finere anatomiske Bygning og Udviklingshistorien 
angaar, saa finder jeg, at denne vigtige Del af Pyc- 
nogonidornes Naturhistorie er saa ndtommendo behandlet i 
enkelte af de nyere Vserker, navnlig af Dohrn og Hoek, 
at jeg i denne Henseende kun har lidet eller intet nyt at 
tilfoie. 
The new species given below, the author has before 
briefly characterized in 3 preliminary Reports in Archiv 
tor Mathematik og Naturvidenskab. Some of these species, 
mentioned here for the first time, have been in part met 
with by subsequent naturalists, and described and figured 
in detail, though not so fully as, in my opinion, to render 
a new description superfluous. 
The descriptions and figures of Pycnogonids by ear- 
lier authors are as a rule exceedingly defective ; and lienee 
we find it a matter of very great difficulty to identify the 
species they institute, nay in some cases actually impos- 
sible. Meanwhile, I certainly think that some of the re- 
cent authors fail to show sufficient discretion, rejecting as 
unserviceable a greater number of descriptions than strictly 
requisite. This would more especially seem to be the case 
with Dohrn, which indeed appears from the singular fact, 
that all the species he mentions from the Bay of Naples are 
described as new, save only Rhynchothorax mediterraneus, 
and yet although not a few Mediterranean forms had been 
previously described, nay some from even the same locality. 
That several of the new species mentioned in Dohrn’s 
work are really identical with species formerly established, 
I regard as unquestionable; and I have reason to believe 
that several ol tin 1 , new genera will prove untenable as 
such. Regarding the Northern species, I have collated 
with the greatest possible care earlier descriptions and 
feel warranted in re-establishing divers wholly forgot- 
ten or ignored species instituted by earlier naturalists 
(e. g. Goodsir). 
The exposition given in this work is of a purely des- 
criptive character, and its chief aim is merely, by a thorough 
comparative examination of the more general structural 
details, to attain a more precise determination of the 
genera and species belonging to the Northern Pycnogo- 
nidian fauna. As regards the more delicate anatomical 
structure and the development, I find this important part 
of the natural history of the Pycnogonids so exhaustively 
treated of in some of the more recently published works, 
especially those of Dohrn and Hoek, that T have but 
little if anything to add in this respect. 
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