2 
ved en Sammenligning med Dohrn’s Vaerk strax fakle i 
0inene, at denne Fauna’s Character er meget vmsentlig 
forskjellig fra den i Middelhavet raadende. Navnlig er 
den store Artsrigdom inden Nymphonidernes Familie i hoi 
Grad characteristisk for de nordlige Have i Modstetning til 
Middelhavet, hvor hidtil kun en eneste herhcn horende Art 
er bleven observeret. Ogsaa er de i de nordlige Have 
forekommendo Former idethele af betydelig storre (tildels 
colossale) Dimensioncr end de i Middelhavet forefnndne, 
som i Sammenligning med hine er gjennemgaaonde rene 
Dvaergformer. 
Yed den systematiske Inddeling af de nordiskc Pyc- 
nogonider har jeg tildels fundet at burde tage Familierne 
i en noget snsevrere Begrmndsning end af tidligere For- 
skere sajdvanlig gjort, hvorved selvfolgelig Familiernes An- 
tal er bleven noget foroget. Eukelte tidligere opstilledo 
Slaegter, som af senere Forskere igjen er inddragne, har 
jeg ligeledes fundet paany at maatte haevde, ligesom en 
Del nye Slregter er opstillede. Jeg anser dot for meget 
sandsynligt, at man ved et fuldstamdigere Kjondskab til de 
existercrule Arter vil iinde .det nodvendigt at gaa endnu 
videre i denne Retning, og at ogsaa en hoiere Inddeling af 
Familierne i Ordener engang vil blive ctableret, hvacl der 
dog tor Tiden vanskeligt lader sig gjennemfkre. 
Angaaende Tenninologien, saa hersker her, som ogsaa 
inden andre Grupper af Arthropoderne, stor Uoverensstem- 
melse mellem forskjellige Autores. E foyer, der i Lighed 
med Milne- Edwards var most tilboielig til at henregne 
Pycnogoniderne til Orustaceerne, benytter saaledes Termini 
hentede fra disse sidste Dyr (Mandibler, Maxiller, Rostrum), 
medens andre Forskere, der holdt paa Pycnogonidernes Af- 
finitet med Arachniderne, anvender paa de sammeDele ganske 
andre Betegnelser, mere i Overonsstemmelse med den for sidst- 
nsevnte Classe smdvanlig brugelige Terminologi. Navnlig vil 
man tinde, at de forreste Par Lemmer figurerer bos de for- 
skjellige Autores under do mest forskjelligartede Betegnelser 
(Mandibler, Antenner, Kiudbakkeantenner, Pedipalpi, Kjm- 
vefodder etc.). Af de nyere Forfattcrc har Hoek i alt vae- 
sentligt henholdt sig til den tidligere mest brugelige Ter- 
minologi, medens Dolirn har for Lemmernes Vedkommende || 
opgivet enhver sserskilt Betegnelse, idet han blot beskriver 
deni efter deres Olden som No. I, II, III etc. Dette er 
vistnok en meget nem Maade at undgaa alle Yanskelighe- 
der, men Methoden er neppe praktisk og vil derfor vistnok 
ikke blive adopteret af andre Forskere. En Terminologi 
taar man nok bekvemme sig til at anvende; men jeg tror, 
at man her gjor rigtigst i at vielge saavidt muligt indiffe- 
rente Betegnelser, der ikke involvercr nogen Homologise- 
ring rued Lennnorne har andre Arthropoder. Nedenfor 
meddeles de af mig i nmrvmrende Arbeide benyttede Ter- 
mini, hvis naermere Forklaring vil sees af hosstaaende 
Figur, forestilleude en Nymphon-Art seet fra Rygsiden, 
med kun en af Fodderne tegnet. 
to be essentially different from that of the Mediterranean 
forms. In particular, the great number of species belong- 
ing to the family Nymphonidce is eminently characteristic 
of the Northern Seas as contrasted with the Mediterranean, 
where but a single species referrable to that family has 
been observed. Moreover, the forms inhabiting the Northern 
Seas attain as a rule much larger dimensions (some are 
even gigantic) than those occurring in the Mediterranean, 
which, compared to the former, must be regarded as 
veritable dwarf-forms. 
In working out the systematic classification of the 
Northern Pycnogonidea, the author lias partly found reason 
to take the families in a somewhat more restricted sense 
than generally done by earlier naturalists, thus occasioning 
a slight augmentation in the number of families. A few 
formerly established genera, rejected by subsequent zoolo- 
gists, he has also seen fit to maintain, and some new 
genera have likewise been instituted. I regard as highly 
probable, that a more intimate acquaintance with the 
existing species will of necessity lead still farther in the 
same direction, and also that a higher division of the 
families into orders must eventually be made, though at the 
time being such an innovation would most certainly prove 
difficult to carry out. 
As regards the terminology, very considerable dis- 
agreement is found to prevail, alike in this group and in 
other divisions oi the Arthropoda. Kroyer, who, in com- 
mon with Milne-Edtvards, felt most inclined to class the 
Pycnogonids with the Crustaceans, adopts terms taken from 
the latter animals (mandibles, maxillae, rostrum), whilst 
other authors, that held to the affinity of the Pycnogonidea 
with the Arachnida, apply for the same parts totally dif- 
ferent appellations, more in accordance with the termino- 
iogy in general use for the latter class. In particular, 
it will be found that the foremost pair of limbs figure 
among the various authors under the most heterogeneous 
designations (mandibles, antennae, maxillary palps, pedipalpi, 
maxillary feet, etc,). Of later authors, Hoek has kept in 
all essentials to the terminology most in use formerly, 
whereas Dolirn, as regards the limbs, has rejected every 
separate appellation, simply describing them in their natural 
older, as No. I, II, III, etc. This is certainly a very 
convenient way of getting over difficulties, but the method 
can hardly be termed practical, and therefore stands little 
chance of being adopted by other authors. A terminology 
of some kind we must submit to use; but in my judgment 
we should as far as possible make choice of indifferent 
terms that do not involve anything homologous with the 
limbs in other Arthropoda. Overleaf are given the terms 
employed in the present Memoir, the more precise signi- 
fication of which will be seen from the accompanying figure, 
that 1 represents a species ofNymphon, — dorsal aspect, — 
with only one of the legs fully drawn. 
