i September samme Aar og opholdt mig her fra den 
9de til den 15de. Limnadierne var nu meget sjeldne, 
men adskilligt storre end de tidligere fundne, skjondt 
ingen oversteg en Lengde af 12 mm. Foruden i 
det omtalte Tjern fandt jeg den ogsaa paa nogle 
andre Steder af Yen, tildels i yderlig smaa Vand- 
ansamlinger, dog her af mindre Storrelse. Derimod 
fandtes den ikke paa en eneste af de mange omlig- 
gende Wer. Ogsaa det folgende Aar gjenfandt jeg 
denne Form i Begyndelsen af August paa de samme 
Steder, men ingen storre end de tidligere indsam- 
lede. Sommeren 1888 fandt Prof. Collett denne 
Phyllopode paa en ganske anden Lokalitet, nemlig 
i en liden Vandkulp i Nerheden af Hamar. For at 
undersoge denne nye Lokalitet noiere, reiste jeg 
derop den folgende Sommer i August, og jeg havde 
ikke synderlig Vanskelighed ved, efter Prof. Colletts 
nermere Angivelser, at finde den omhandlede Kulp. 
Den var imidlertid nu fuldstendig udtorret paa 
Grund af lengere Tids forudgaaende tort Veir, saa 
jeg alene kunde forsyne mig med noget af det ind- 
torrede Mudder for senere kunstige Udkleknings- 
forsog. To Gange senere har jeg besogt den samme 
Lokalitet, nemlig i Begyndelsen af September 1894 
og i Midten af Juli 1895. Begge Gange fandtes 
tilstrekkeligt Vand i Kulpen og store Mengder af 
forskjellige Entomostraceer, men af Limnadier var 
der intetsomhelst Spor at opdage, hverken Larver 
eller voxne, saa det nesten ser ud til, at den nu 
her er fuldsteendig uddeet, for kanske efter en lang 
Aarrekke paany at optrede ligesaa pludselig som 
den er forsvunden. Heller ikke af det Mudder, der 
paa disse 2 Udflugter medtoges fra Kulpen har jeg 
-kunnet udklekke en eneste Limnadia, medens mine 
mange Gange gjentagne Udklekningsforsog med det 
i 1889 samlede Mudder aldrig har slaaet feil. Idet- 
hele synes, ogsaa efter andre Forskeres Beretninger, 
denne Phyllopodes Optreden at vere yderst lune- 
fuld. Et Aar kan den treffes i storste Mengde 
paa et begreendset Omraade, for saa igjen sporlost 
‘at forsvinde, og forst efter lange Aarrekker kan 
den saa optrede igjen enten paa samme Lokalitet 
eller paa Steder, hvor man tidligere aldrig har fun- 
det den. 
Angaaende denne Forms Levevis forovrigt, saa 
synes overalt kun et enkelt Kuld Individer at ud- 
vikle sig for hver Sommer. Man har ialfald hidtil 
ingen sikre Data for, at flere Generationer har fulgt 
paa hinanden samme Aar. Individernes Livsperiode 
synes i Regelen kun at vere indskrenket til et 
Par Maaneder, ofte kanske ikke engang saa lenge. 
Men i Lobet af denne korte Tid vil ialfald en Del | 
af Individerne naa til Kjonsmodenhed og kunne af- 
largest specimens were about 10 mm. long, and had 
5 pairs of lines of growth, In order to find, if pos- 
sible, full-grown specimens, I again visited the island 
in September of the same year, and stayed there 
from the 9th to the 15th. The Limnadix were then 
very rare, but considerably larger than those pre- 
viously found, although none exceeded a length of 
12 mm. I also found it in other places on the 
island besides the above-mentioned lake, sometimes 
in exceedingly small accumulations of water, though 
then of a smaller size. On the other hand it was 
not to be found on a single one of the ‘many sur- 
rounding islands. In the following year also, I 
found this form again in the beginning of August 
-in the same places, but none larger than those pre- 
viously taken. In the summer of 1888, Prof. Collett 
found this Phyllopod in quite another locality, 
namely in a little pool in the neighbourhood of 
Hamar. In order to examine this new locality 
more minutely, I went up there the following sum- 
mer in August, and, from Prof. Collett’s exact des- 
cription, had not much difficulty in finding the pool 
in question, It was however completely dried up, 
owing to the preceding long period of dry weather, 
so that all I could do was to take away with me 
some of the dried mud, in order to attempt arti- 
ficial hatching at a future time. Twice subse- 
quently have I revisited the same locality, namely, 
in the beginning of September, 1894 and in the 
middle of July, 1895. Both times I found sufficient 
water in the pool, and large numbers of various 
Entomostraca, but no trace of Limnadia was to be 
discovered, whether larva or adult, so that it almost 
‘appears as if it were now completely extinct, per- 
haps to appear again after a number of years as 
suddenly as it has disappeared. Nor yet have I 
succeeded in hatching one single Limnadia out of 
the mud brought away from the pool on these 
two excursions, while my oft-repeated hatching 
attempts with the mud collected in 1889 have never 
failed. It seems, on the whole, as also from the 
accounts of other naturalists, that the appearance 
of this Phyllopod is extremely capricious. One year 
it may be met with in large numbers over a limited 
area, then vanish utterly, and only after many 
years may appear again, either in the same loca- 
lity, or in places where it has never been found 
previously. 
With regard to the habits of this form in 
other respects, it always appears that only a single 
brood of animals is developed each summer. We 
have not, at any rate up to the present, any cer- 
tain data to prove that several generations have 
succeeded one another in the same year. The living 
-period of the individual animals seems as a rule to 
be limited to a couple of months, frequently perhaps 
even less. But in the course of this short time 
