144 
at kun et meget begrrendsot Antal Familier har vseret op- 
stillet; ja det er egentlig forst i den allernyeste Tid at 
der overhovedet har vseret Tale om nogen Sondring raellem 
forskjellige Familier inden denne Dyrgruppe. Ved Bear- 
beidelsen af de nordiske Fycnogonideer bar jeg fundet det 
nodvendigt noiere at praicisere ilcke blot Slaegterne, men 
ogsaa Familierne, og liar idethele, som det vil sees, taget 
disse sidste i en betydelig smevrere Begnendsning end af 
andre Forskefe gjort. Folgen heraf er, at deres Tal er 
bleven betydelig foroget. Medens Hoek, i sine nyeste 
Arbeider over disse Dyr, kun opstiller 4 Familier, er deres 
Tal i nservserende Arbeide fordoblet; ja jeg finder nu hertil 
at maatte foie endiiu en ny Familie, idet Skegten Phoxi- 
chilus synes mig ved nsermere Overveielse neppe at kunne 
forenes med SI. Pycnogonum i en og samme Familie, men 
bor danne Typen for en sierskilt saadan, Phoxichilidce. 
Antallet al Familier, i den Begraendsning hvori jeg her 
tager dem, bliver altsaa ialt ikke mindre end 9. De er i 
nrervrerende Arbeide opfortc i en bestemt Rmkkefolge, 
hvorved jeg har villet antyde den stprre eller mindre Grad 
af Aifinitet, de viser indbyrdcs. Jeg finder imidlertid nu 
at burde forsoge endnu mere bestemt at fastsiette dette 
indbyrdes Forhold mellem Familierne ved at gruppere dem 
under 3 storre Afdelinger. Som Distinctionscharacter har 
jeg herved hovedsageligt benyttet Forholdet af Saxlem- 
merne. Hos en Gruppe af Pycnogonideer mangier disse 
(ligesom ogsaa Folerne) fuldstsendigt, naar undtages i Larve- 
tilstanden; hos en anden Gruppe er de deriinod vel ud- 
viklede gjennem li^le Dyrets Levetid; hos en tredie Gruppe 
endelig er disse Lemmer vistnok i Regelen tilstede i Ung- 
dommen (altsaa ikke blot i Larvetilstanden), hvorimod de 
i den fuldt • udviklede Tilstand enten reduceres til unyttige 
Appendices eller ganske og aldeles forsvinder. Herefter 
faar vi altsaa 3 store Afdelinger eller Ordener, hvorunder 
alle bekjendte Pycnogonideer lader sig indordne. De i 
det foregaaende nairmcre omtalte nordiske Pycnogonide- 
Skegter lader sig ifolge ovenstaaende Inddeling sarnmen- 
stille paa folgende Maade: 
Ordo I. 
Aclrelata. 
Fam. 1. Pycnogonidce. 
Gen. 1. Pycnogonum. 
Fam. 2. Phoxichilidce . 
Gen. 2. Phoxichilus. 
. Ordo II. 
Kaclielata. 
Fam. 1 . Pho xi chili diidce. 
Gen. i. Phoxichilidium. 
2. Anoplodactylus. 
that only a very limited number of families has been 
established; indeed, it is only first in quite late times that 
there has been any mention at all of a separation between 
the different families included in this animal group. In 
the treatment of the northern Pycnogonids I have found 
it necessary to define more minutely, not only the genera 
but also the families, and have, as will be seen, taken 
those last in. altogether, a considerably narrower limitation 
than other naturalists have done. Their number has, con- 
sequently, been considerably increased. While Hoek, in 
his latest work on those animals, only establishes 4 families, 
their number has been doubled in the present work ; indeed 
I now find it necessary to add to this yet another, new 
family, inasmuch that the genus Phoxichilus appears, to 
me, on closer consideration, to be scarcely -alliable with 
the genus Pycnogonum in one and the same family, but 
ought to form the type of a separate one, Phoxichilidce. 
The number of families, within the limitation in which I 
here take them, becomes consequently, altogether, not less 
than 9. They are in the present work arranged in a 
definite consecutive order, by which I have desired to in- 
dicate the greater or lesser degree of affinity they mutually 
show among themselves. I think, however, nowq that I 
ought to attempt to still more definitely establish the 
mutual relations between the families, by grouping them 
in 3 large divisions. As distinctive characters I have, in 
doing so, principally adopted the relations of the chelifori. 
In one group of Pycnogonids these are entirely awanting 
(as well as also the palpi) except in the larval state; in a 
second group, they are, on the other hand, well developed 
throughout the entire existence of the animal; finally, in 
a third group, those limbs are certainly, as a rule, present 
in the young stages (not only in the larval state there- 
fore) but, on the contrary, they, in the fully developed 
condition, become either reduced to useless appendices, or 
quite, and absolutely, disappear. According to this, there- 
fore, we obtain 3 great divisions or orders, within which 
all the known Pycnogonids permit themselves to be ar- 
ranged. The northern genera of Pycnogonids, spoken of 
in the foregoing, permit themselves, according to the above- 
mentioned arrangement, to be ranked in the following 
manner: 
Order I. 
Aclxelata. 
Fam. 1 . Pycnogonidce. 
Gen. 1. Pycnogonum. 
Fam. 2. Phoxichilidce. 
Gen. 2. Phoxichilus. 
Order II. 
Eixclxelata. 
Fam. 1. Phoxichilidiidce. 
Gen. 1. Phoxichilidium. 
„ 2. Anoplodactylus. 
I 
