verende Form viser mest Afinitet. At den imid- 
lertid ikke lengere kan opfattes som en virkelig 
Phyllopode, derom kan der vel neppe for Tiden vere 
mere end en Mening, efterat dens anatomiske Byg- 
ning, naynlig ved Prof. Claus’s udmerkede Under- 
sogelser, er bleven noiere udredet. Sporgsmaalet er 
nu, om de Hiendommeligheder, denne Form viser i 
anatomisk Henseende, gjor det absolut nedvendigt at 
skille den helt ud fra de ovrige Entomostraceer som 
Typen for en egen Orden. Saagodtsom samtlige 
Forskere synes for Tiden i Virkeligheden at vere 
af denne Mening, og baade Packard’s Benevnelse 
Phyllocarida og den af Claus foreslaaede Leptostraca 
er beregnet paa at udtrykke en distinct Orden. 
Underssger vi imidlertid, hvorledes Forholdet er 
med de for Tiden ialmindelighed til Branchiopodernes 
Orden henforte Former, saa vil vi ogsaa her stode 
paa serdeles store og vesentlige Forskjelligheder i 
den anatomiske Bygning; ja de saakaldte Branchiurer 
(Argulus), som vel de fleste Forskere nu er enige 
om at henfore til Branchiopodernes Orden, forekom- 
mer mig endog, saavel hvad den ydre Habitus som 
den indre Organisation og Levevis angaar, at skille 
sig endnu betydelig mere fra de typiske Branchio- 
poder end Tilfeldet er med Nebalia. Hos denne 
sidste Slegt er der ialfald en Character, og det 
netop den for Branchiopodernes Orden mest beteg- 
nende, der staar i den bedste Harmoni med hvad vi 
finder som typiskt for denne Krebsdyrgruppe; jeg 
mener Forkropslemmernes Bygning. Disse viser ikke 
blot ved sin udpreget bladdannede Form den storste 
Lighed med samme hos virkelige Branchiopoder; 
men, hvad der er af end storre Vegt, deres respi- 
ratoriske Function er fuldkommen ligesaa tydeligt 
udpreget som hos de mest typiske Former blandt 
- hine. Alene denne ene Character synes mig at 
maatte stemple Slegten Nebalia som en veritabel 
Branchiopode, og ialfald at vere af adskillig storre 
Vegt.end Mesteparten af de Characterer, man har 
anfert for at modbevise en saadan Antagelse, og 
hvoraf flere faktisk er fuldsteendig ubrugelige. Efter 
min Mening bor derfor Slegten Nebalia henfores til 
Branchiopodernes Orden, om den end her maa danne 
Typen for en egen, i visse Henseender meget ano- 
mal Afdeling eller Underorden, for hvilken den forst 
af Packard foreslaaede Benevnelse Phyllocarida vil 
kunne bibeholdes. 
I den nyere Tid har man troet i nogle, tildels 
kjempemessige, fossile Former fra den paleozoiske 
Formation (Ceratiocaris, Dithyrocaris ete.) at gjen- 
kjende visse for Slegten Nebalia eiendommelige Cha- 
racterer, saaledes Legemets almindelige Form, Ud- 
viklingen af Rygskjoldet og navnlig den meget 
characteristiske bevegelige Pandeplade; og, skjondt 
stracans, and among these the Branchiopods are 
those with which the present form exhibits most 
affinity. That it may, however, be no longer regarded 
as a genuine Phyllopod, there can, now be scarcely 
any diversity of opinion since its anatomical struc- 
ture has been precisely elucidated, especially through 
Prof. Claus’s admirable investigations. The question 
now is, whether the peculiarities this form exhibits 
in anatomical respects makes it absolutely neccessary 
to separate it entirely from the other Entomostra- 
cans, as the type of a special order. Nearly all 
investigators appear, at present, to really entertain 
that view, and both Packard’s appellation, Phyllo- 
carida, and that proposed by Claus, Leptostraca, are 
intended to express a distinct order. If we, how- 
ever, investigate what the relations of the forms at 
present generally assigned to the order of Branchio- 
pods are, we will also here meet with particularly 
great and material divergencies in the anatomical 
structure; indeed the so-called Branchiura (Argulus), 
which most investigators are now, we think, unan- 
imous in assigning to the order of Branchiopods, 
. yet appears to me, both in regard to external habi- 
tus, internal organization, and the mode of life, to 
distinguish itself even more considerably from the 
typical Branchiopods than is the case with Nebalia. 
In the latter genus there is, at any rate, one char- 
acter, and just the one most characteristic of the 
order of Branchiopods, which stands in the most 
perfect harmony with what we find to be typical 
in that group of Crustaceans. I refer here to the 
structure of the appendages of the anterior division 
of the body. These exhibit, not only in their dis- 
tinguished foliaceous form the greatest similarity 
with the same limbs in genuine Branchiopods, but, 
what is of still greater importance, their respira- 
tory function is perfectly as prominent as in the 
most typical form of Branchiopods. That single 
characteristic alone, it appears to me, must stamp 
the genus Nebalia as a true Branchiopod, and, in 
any case, is of considerably more importance than 
the greater part of the characteristics that have 
been adduced to disprove such an assumption, and 
some of which are really perfectly unserviceable. 
In my opinion the genus Nebalia ought, therefore, 
to be assigned to the order of Branchiopods, even 
although it here must form the type of a special, 
jn certain respects very anomalous division or sub- 
’ order, for which the appellation Phyllocarida, first 
proposed by Packard, may be retained. 
In later times it has been thought, that we, in 
some partly gigantic fossil forms from the Paleo- 
zoic formation (Ceratiocaris, Dithyrocaris &c.) were 
able to recognize certain characteristics peculiar to 
the genus .Nebalia, for instance the general form 
of the body, the development of the carapace, and 
especially the very characteristic mobile frontal 
