skiftningen er Valvlerne forsynede med nok en 
Vextstribe udenom den Iste, en ny Aigmasse dan- 
nes og saaledes fremdeles. Antallet af paa hinan- 
den folgende Hudskiftninger er derfor, iberegnet den, 
der er gaaet umiddelbart forud for 1ste postlarvale 
Stadium, noiagtig det samme som Antallet af Vext- 
striber paa hver Valvel, og omtrent ligemange 
Gange har i Regelen Individet afsat en Aigmasse. 
Efterhvert som Skallen paa denne Maade ved ny- 
dannede periphere Lag tiltager i Storrelse, foran- 
dres lidt efter lidt dens Form, idet Rygkanten bli- 
ver mere og mere buet isin forreste Del. Samtidigt 
bliver de primere Valvler ligesom skudt fortil og 
indtager tilsidst en forholdsvis liden Del af Skallen 
ved dennes overste forreste Hjorne, hvilket sidste i 
samme Forhold bliver utydeligere og mere afstumpet 
(se Fig. 1). Hos meget gamle Individer antager 
Skallen tilsidst, seet fra Siden, en nesten trianguler 
Form, med den primere Area skudt helt fortil og 
neesten umboformigt fremragende, saaledes som an- 
tydet paa den af Prof. Lilljeborg givne Figur 
(Skallen i naturlig Storrelse). 
Forekomst og Levevis. 
Allerede Grube har opgivet, at der i Berliner- 
Museet findes opbevaret Exemplarer af denne Form, 
indsamlede af H. Rathke i Norge. Men da dette 
Fund ikke med et eneste Ord er omtalt i den sidst- 
neevnte Forskers bekjendte Verk: «Beitrage zur 
Fauna Norwegens», og jeg sely under mine mange- 
aarige Undersogelser af vor Ferskvandsfauna aldrig 
havde paatruffet den, fandt jeg Paalideligheden af 
denne Opgift af Grube meget tvivlsom og udtalte 
mig ogsaa derhen i en i Vid. Selsk. Forhandlinger 
meddelt forelobig Meddelelse om Norges Phyllopoder. 
Forst i Aaret 1885 lykkedes det mig med fuld Sik- 
kerhed at faa constateret denne eiendommelige Phyl- 
lopodes Forekomst her i Landet. Under en Reise, 
jeg dette Aar foretog langs Sydkysten af Landet, 
tog jeg d. 22de Juli Station paa en ikke meget stor - 
og temmelig flad 0, «Merdo», udenfor Arendal, og 
fandt her allerede den forste Dag efter min Ankomst 
store Mengder af Limnadia-Larver i et grundt med 
Gresbund forsynet Tjern, «Storekjer» kaldet, be- 
liggende omtrent midt paa Men. Paa denne Tid var 
kun meget faa Exemplarer naaet ud over Larve- 
tilstanden, men i Lobet af de folgende Dage op- 
traadte postlarvale Stadier i stor Mengde, og ved 
Slutten af Maaneden var ingen Larve lengere at 
finde. Flere Exemplarer var da allerede egbe- 
rende og havde Valvlerne forsynede med de forste 
Vextstriber. Ved min Afreise, d. 10de August, var 
Skallen hos de storste Individer omtrent 10 mm. 
lang og hayde 5 Par Vextstriber. For om muligt 
at finde fuldvoxne Individer, besogte jeg igjen Wen 
110 
skin, out of the shell behind. After the exuviation 
the valves acquire another line of growth outside 
the first, a new mass of eggs is formed, and so on. 
The number of successive exuviations, including 
that which immediately preceded the 1st post-larval 
stage, is therefore exactly the same as the number 
of lines of growth on each valve, and the animal 
has, as a rule, deposited a mass of eggs about the 
same number of times. While the shell in this 
manner increases in size by the addition of new 
peripheral layers, it gradually changes its shape, 
the dorsal edge becoming more and more curved in 
its front part. At the same time the original valves 
are as it were pressed forward, and at last occupy 
a comparatively small part of the shell at its upper 
front angle, which also, in the same proportion, be- 
comes more indistinct and blunter (see fig. 1). In 
very old specimens the shell, seen from the side, at 
last assumes an almost triangular shape, with the 
original area pushed right to the front, and pro- 
jecting almost umbonately, as indicated in the 
figure given by Prof. Lilljeborg (the shell in its 
natural size). 
Occurrence and Habits. 
Grube has already stated that in the Berlin 
Museum there are preserved specimens of this form, 
collected by A. Rathke in Norway. But as this 
discovery is not so much as named in the latter 
naturalist’s well-known work «Beitriige zur Fauna 
Norwegens», and I myself, during my many years’ 
investigations of our (Norwegian) fresh-water fauna, 
had never met with the form, I considered the 
trustworthiness of Grube’s statement to be very 
doubtful, and expressed myself to that effect in a 
preliminary account of the Phyllopoda of Norway 
in the Viden. Selsk. Forhandlinger (Proceedings of 
the Scientific Society). Not. until the year 1885 did 
I succeed in substantiating with certainty the 
occurrence of this peculiar Phyllopod in this country 
(Norway). During a journey I made that year 
along the south coast, I stopped, on the 22nd July, 
at a rather flat, and not very large island off Aren- 
dal, called «Meerdo», and there found, on the very 
day after my arrival, large numbers of Limnadia 
larve in a shallow lake called «Storekjer», situated 
in about the middle of the island, and with a grassy 
bottom. At that time only a very few specimens 
were advanced beyond the larval condition, but in 
the course of the few following days, post-larval 
stages made their appearance in great numbers, and 
by the end of the month there was not a larva to 
be found. Several specimens were then already 
carrying eggs, and had their valves furnished with 
the first lines of growth. At the time of my 
departure, the 10th August, the shells on the 
