—-_  _ 
Blodkarsystemet. 
Hjertet (Fig. 1, Fig. 2, c) er af langstrakt spindel- 
dannet Form og strekker sig, umiddelbart ovenfor 
Tarmen, igjennem hele Midtkroppen og Storsteparten 
af Bagkroppen, endende omtrent ved Enden af den- 
nes 3die Segment. I Midtkroppens 5te Segment har 
det sin sterste Vidde og viser her til hver Side en 
meget iginefaldende Tverspalte. En lignende, men 
betydelig mindre Spaltaabning sees til hver Side 
helt fortil, ved Hjertets Begyndelse. Claus har 
desuden afbildet, mellem begge Par, 4 meget smaa 
dorsale Spaltaabninger, som det dog ikke er lykkets 
mig at faa se tydeligt. Fra Hjertets forreste Ende 
udgaar en, ialfald i sit inderste Parti tydelig Arterie, 
og ogsaa Hjertets bagre Ende har forekommet mig 
at fortsette sig i en lignende bagudlobende Arterie. 
Noget virkeligt udviklet Blodkarsystem synes dog 
neppe at vere tilstede, og Blodet circulerer, som 
hos andre lavere Crustaceer, vesentlig kun i veg- 
lose Hulrum mellem Bindevevet og Musklerne. 
I Branchialfodderne er allerede omtalt Tilstedeve- 
relsen af saadanne med hinanden anastomoserende 
Blodgange, navnlig i de 2 ydre Vedheeng (Exopodit 
og Epipodit). Et lignende System af veglose Blod- 
kanaler findes ogsaa mellem Rygskjoldets 2 Lamel- 
ler, og da Cirkulationen her er meget livlig, har 
man Grund til at antage, at Rygskjoldet spiller en 
ikke uvesentlig Rolle ved Dyrets Respiration. 
Nervesystemet. 
At undersoge Nervesystemet i sine Detailler, 
er forbundet med serdeles store Vanskeligheder, da 
dets Centraldele ligger.saa tet omgivne af Muskler 
og Bindeveev, at de yderst vanskeligt lader sig 
isolere ved Disection. Paa Tversnit af Kroppen 
(Pl. V,Fig. 2) kan man dog let orientere sig angaaende 
Buggangliekjedens Beliggenhed (g), og kan herefter 
bestemme dens Plads ogsaa i Profil af Dyret (se 
Fig. 1). Hjernegangliet har det kun lykkets mig 
at se temmelig ufuldstendigt, Det synes ikke at’ 
vere af nogen betydelig Storrelse, og udsender, for- 
uden Synsnerverne, sterke Nervestammer til de 
2 Par Folere. I Midtkroppen ligger de enkelte 
Knuder af Buggangliekjeden tet sammen, kun for- 
bundne med meget korte og tykke Lengdecommis- 
surer, mellem hvilke der knapt er noget Mellemrum. 
Selve Ganglierne er forholdsvis smaa og alle af ens 
Storrelse, deres 2 Halvdele fuldkommen -sammen- 
4—G. 0. Sars: Fauna Norvegie. 
(ed, ev), grouped nearly in the form of a rosette, 
around and close in to the intestine, with a somewhat 
largish interval between the dorsal pair. 
The blood-vessel system. 
The heart (fig. 1, fig. 2 c) is of elongate, fusi- 
form shape, and extends, immediately above the 
intestine, through the entire mesosome and the 
greater part of the metasome, terminating at about 
the extremity of the 3rd segment of the latter. 
It has its greatest breadth in the 5th segment of 
the mesosome, and exhibits here on either side a 
very prominent transversal fissure. A similar. but 
considerably smaller fissure-aperture is seen on each 
side, quite in front, at the commencement of the 
heart. Claus has illustrated besides, between both 
pairs, 4 very small dorsal fissure-apertures, which 
I have, however, not been fortunate enough to ob- 
serve distinctly. From the foremost extremity of 
the heart there issues a, at least in its innermost 
portion, distinct artery; and also the posterior ex- 
tremity of the heart has appeared, to me, to con— 
tinue itself in a similar backward running artery. 
Any real, developed blood-vessel system scarcely 
appears, however, to be present; and the blood 
circulates, as in other lower Crustaceans, princi- 
pally, only in cavities, without walls, between the 
connective-tissue and the muscles. In the branchial 
feet, the presence of such blood pasages, anastom- 
osing with each other, has already been mentioned; 
especially in the 2 outer appendages (exopodite and 
epipodite). A similar system of blood-ducts, without 
walls, is also found between the 2 lamelle of the 
carapace, and as the circulation is here very active 
there is reason to suppose that the carapace plays 
a not unimportant part in the respiration of the 
animal. 
The nervous system. 
To investigate the nervous system in its details 
is a matter of particularly great difficulty, as its 
central portions lie so closely surrounded by muscles 
~and connective tissue that it is excessively difficult 
to isolate them by dissection. In transversal sec- 
tions of the body (Pl. V, fig. 2) we can, however, easily 
obtain information concerning the situation of the 
ventral ganglial chain (g), and can from this deter- 
mine its situation also in a side-view of the animal 
(see fig. 1). I have not been fortunate enough to 
observe the ganglion of the brain very perfectly. It 
does. not appear to be of any considerable size, and 
sends off, besides the optical nerves, powerful ner- 
vous stems to the 2 pairs of antenne. In the meso- 
some, the individual knots of the ventral ganglial 
chain lie close together, only connected by very 
short and thick longitudinal commissures, between 
which there is scarcely any interval. The ganglia 
