————— ee 
105 
tydeligt sondrede, idet der mellem dem ogsaa dor- 
salt er en temmelig dyb Indbugtning. Hovedet er 
jevnt hvelvet oventil og afrundet fortil, med et 
stumpt Fremspring nedenfor det enkle @ie, forestil- 
lende Anlegget til Rostrum. Umiddelbart bag dette 
Fremspring sees de endnu knudeformige 1ste Par 
Folere at udgaa. Bag disse igjen rager den enormt 
udviklede Overlebe frem, med sin skraat nedad- 
rettede pigformige Endefortsats. Ved dennes Basis 
er der indad en liden cilieret Lap, der seedvanligvis 
er boiet ind mod Mundaabningen og som svarer til 
den verticalt stillede Endelamelle hos det voxne 
Dyr. Til hver Side af Mundaabningen sees de nu 
vel udviklede Kindbakker, fra hvis ydre Side Man- 
dibularfodderne udgaar, og umiddelbart bag dem 
igjen viser sig Anlegget til de 2 Par Kjever. Ryg- 
skjoldet har nu udviklet sig til en kappeformig 
Hudduplicatur, bestaaende af 2 symetriske Halvdele 
skilte bagtil i Midten ved en dyb Indbugtning. 
Det har nu tydeligt sondret sig ogsaa fortil; men 
de 2 Halvdele gaar ganske umerkeligt over i hin- 
anden dorsalt, uden at der endnu er nogen tydelig 
Sondring af 2 Valvler. De sig udviklende Fodder, 
der nu fuldstendig dekkes oventil af Rygskjoldet, 
har forlenget sig til noget polseformige Fortsatser, 
der er rettede skraat bagtil og ligger tet sammen. 
Den bagerste Del af Kroppen er ganske svagt om- 
beiet mod Bugsiden og begynder at sondre sig som 
en tydelig Haledel. De terminale Fortsatser viser 
sig nu klarlig at vere identiske med de senere be- 
vegeligt til Enden af Haledelen indleddede Hale- 
klor. I nogen Afstand fra dem paa Dorsalsiden har 
allerede Haleborsterne udviklet sig; derimod er der 
endnu ikke noget Spor af de for det voxne Dyr 
characteristiske tandede Haleplader. Af de For- 
andringer, der er foregaaet med den indre Organi- 
sation kan nevynes, at de i tidligere Stadier simple 
_blindsekformige Udvidninger af Tarmens forreste 
Del har hver sondret sig i en dorsal og en ventral 
Lap, og at Hjertet har dannet sig i den forreste 
Del af Truncus. 
Sidste Larvestadium er fremstillet Fig. 7, fra 
Rygsiden. Legemet har nu en Lengde af 1,14 mm. 
og ligner idethele samme hos de 2 foregaaende Sta- 
dier, dog med den Forskjel, at Hovedets Pandedel 
er noget mere fremspringende, og at Rygskjoldet 
er betydelig storre. Dette sidste dekker nu som 
en bred Kappe Storsteparten af Truncus tilligemed 
de til samme horende Lemmer oventil og har bagtil 
et dybt Indsnit. Fodderne, hvis Antal fremdeles 
-kun er 6 Par, er endnu fuldstendig ubevegelige, 
men har nu sondret sig i sine respective Hoved- 
-afsnit, hvoraf navnlig Epipoditerne er meget tyde- 
lige i Dyrets dorsale Stilling. Fra Enderne af Fod- 
derne er allerede korte Borster begyndt at spire 
14 — G. 0. Sars: Fauna Norvegiz. 
very distinctly defined, as there is, dorsally too, a 
rather deep hollow between them. The head is 
evenly arched above and rounded in front, with a 
blunt projection below the ocellus, representing the 
rudiment of the rostrum. Immediately behind this 
projection, the still nodiform 1st pair of antenne 
are seen to issue. Behind them again, projects the 
enormously developed labrum, with its spiniform 
terminal protuberance directed obliquely downwards. 
At its base inside, there is a little ciliated lobe, 
which is usually bent in towards the oral aperture, 
and which corresponds to the vertically-placed ter- 
minal lamella in the full-grown animal. On each 
side of the oral aperture are seen the now well- 
developed mandibles, from the outer side of which 
issue the mandibular legs, and immediately behind 
them again, appear the rudiments of the 2 pairs of 
maxille. The carapace has now developed into a 
hood-shaped cuticular duplicature, consisting of 2 sym- 
metrical halves, separated behind in the middle by a 
deep depression. It has also become well defined 
in front, but dorsally the two halves run quite 
imperceptibly into one another, without as yet any 
distinct division into 2 valves. The developing legs, 
which are now completely covered above by the 
carapace, have lengthened into somewhat sausage- 
shaped protuberances, directed obliquely backwards, 
and lying close together. The hinder part of the 
body is very slightly bent down towards the ventral 
surface, and begins to be marked off as a distinct 
caudal part. The terminal projections now show 
themselves clearly to be identical with the caudal 
claws subsequently movably articulated to the end 
of the caudal section. At some distance from them 
on the dorsal side, the caudal bristles have already 
developed, whereas there is as yet no trace of the 
dentated caudal lamelle characteristic of the adult 
animal. Among the changes that have occurred in 
the internal organisation, it may be mentioned that 
the simple cecal expansions of the front part of the 
intestine in earlier stages, have become marked off 
into a dorsal and a ventral lobe, and that the heart 
has been formed in the anterior part of the trunk. 
In fig. 7, the last larval stage is represented, 
seen from the ventral surface. The body now has 
a length of 1,14 mm., and on the whole resembles 
that in the 2 preceding stages, though with these 
differences, viz., that the frontal part of the head 
is rather more prominent, and that the carapace is 
considerably larger. The latter now covers like a 
broad mantle the upper portion of the greater part 
of the trunk and limbs, and has a deep emargina- 
tion behind. The legs, which still only number 6 
pairs, are as yet quite immovable, but are now divided 
into their respective principal parts, of which no- 
tably the epipodites are very distinct in the ani- 
mal’s dorsal position. From the extremities of the 
