26 
smeltede med hinanden og udsendende 2 sterke | themselves are relatively small and all alike in 
Sidestammer, der udbreder sig dels i Branchial- 
fedderne, dels i Kroppens Muskulatur, De 4 i Bag- 
kroppen beliggende Ganglier er betydelig storre og 
ogsaa mere fjernede fra hinanden, med lengere og 
mere tydeligt skilte Commissurer. I Halen lober 
2 Nervestammer langs ad Bugsiden lige til Hale- 
grenene, og danner for hvert Par af de smaa Hale- 
fodder en liden ganglios Opsvulmning. En lignende 
synes ogsaa at findes ved Basis af Halegrenene. 
Generationsorganerne, 
Ovarierne er til sine Tider meget let at obser- 
vere hos det levende Dyr, da de med stor Tydelig- 
hed skinner igjennem Integumenterne paa Grund af 
sin intense redgule Farve. De danner (se Pl. V, 
‘Fig. 1, Fig. 2, ov) 2 langstrakte Sekke, der streek- 
ker sig, til hver Side af Tarmen, igjennem hele 
Midtkroppen og Bagkroppen og rager endog et 
Stykke ind i Halen. I enhver af Sekkene findes 
kun en enkelt Rekke sig udviklende Adg, alle med 
tydelig Kimblere og grovkornet Blommemasse. Aigge- 
lederne har det ikke lykkets mig at faa se saa tyde- 
ligt, at jeg med Bestemthed kan angive deres Plads. 
Det har imidlertid forekommet mig, at de udmunder 
ved Basis af 6te Par Branchialfodder.. Testes har 
omtrent samme Beliggenhed som Ovarierne og dan- 
ner ligesom disse simple Sekke, men er betydelig 
smalere end disse. De munder, ifolge Claus ved 
Basis af sidste Par Branchialfedder. 
Udvikling. 
JEggene optages, som ovenfor nevnt, efter at 
vere komne ud af Adglederne, i et Slags Rugehule, 
der ligger ind under Midtkroppen, omgiven af Ryg- 
skjoldets Valvler og delvis begreendset af Branchial- ° 
fodderne, hvis talrige krummede Endeborster hindrer 
dem fra at falde ud af Rygskjoldets Hule. De 
undergaar her sin hele Udvikling, og forst naar Un- 
gerne er saa vidt komne, at de med Lethed kan be- 
‘vege sig i Vandet, forlader de Klekkehulen. Ud- 
viklingen er ngiere studeret af den russiske Natur- 
forsker Kowalewsky, og mine Undersogelser stemmer 
i alt vesentligt overens med hvad der af denne ud- 
merkede Forsker er meddelt. ggene er umiddel- 
bart efter at vere optagne i Klekkehulen, af redgul 
Farve og noget oval Form, Senere antager de lidt 
efter lidt en noget lysere Couleur og bliver ogsaa 
mere gjennemsigtige. De er, som hos Flerheden af 
Crustaceerne, meroblastiske, idet Storsteparten af 
size; their 2 halves are completely coalescent with 
each other, and send off 2 powerful lateral stems 
which distribute themselves partly in the branchial 
feet and partly in the muscles of the body. The 4 
ganglia situated in the metasome are considerably 
larger and also situated farther apart from each 
other, with longer and more distinctly separated 
commissures. In the urosome 2 nerve-stems pass 
along on the ventral side, right to the caudal rami, 
and form, for each pair of the small caudal feet, a 
small gangliar swelling. A similar swelling ap- 
pears also to be present at the base of the caudal 
rami. 
The reproductive organs. 
The ovaries are at times very easy to observe 
in the living animal, as they shine through the inte- 
guments with great distinctness, owing to their 
intense red-yellow colour. They form (see Pl. V, 
fig. 1, fig. 2, ov) 2 elongate sacs which extend them- 
selves to each side of the intestine through the 
entire mesosome and metasome, and reach even 
some way into the urosome. In each of the sacs 
there is found only a single series of developing 
ova, all having a distinct germinative vesicle and 
coarsely granular yolk substance. The ovarial 
ducts I have not been fortunate enough to observe 
so distinctly that I can with precision state their 
situation. It has, however, appeared to me that they 
debouch at the base of the 6th pair of branchial 
feet. The testicles have nearly the same situation 
as the ovaries and, like these, form plain sacs, but 
are considerably narrower than them. According to 
Claus they debouch at the base of the last pair of 
branchial feet. 
Development. 
The ova are received, as above stated, after 
having been discharged from the ovarial ducts, in a 
kind of hatching cavity, which is situated in below 
the mesosome, surrounded by the valves of the 
carapace and partly limited by the branchial feet 
whose numerous bent terminal bristles prevent them 
from falling out of the cavity of the carapace. 
They undergo here their entire development, and 
first when the young ones have advanced so far 
‘that they can move themselves with ease in the 
water do they abandon the hatching cavity. The 
development has been closely studied by the Russian 
naturalist Kowalewsky, and my investigations agree 
in all material points with what has been stated 
by that eminent investigator. The ova are, imme- 
diately after having been received into the hatching 
cavity, red-yellow in colour, and somewhat oval in 
shape. Subsequently they, little by little, assume 
