8 
Fam. Limnetide. 
Character. — Skallen sterkt buget, Valvlerne 
uden Veextstriber og forbundne dorsalt med en 
ufuldkommen Laas. Hovedet af enorm Storrelse, 
gaaende ud i et nedadkrummet Rostrum af for- 
skjellig Form hos de to Kjon. Truncus forholdsvis 
kort og massiv; Halen rudimenter. iste Par Folere 
smaa og simple; 2det. Par forholdsvis korte, men 
kraftige. Kindbakkernes Tyggedel stumpt tandet. 
2det Par Kjever rudimentere. Foddernes Antal 
ikke overstigende 12 Par; de ydre Enditer. finger- 
formigt forlengede; kun iste Par hos Hannen 
prehensile. Forplantningen udpreget bisexuel. Ud- 
viklingen en compliceret Metamorphose, begyndende 
med et eiendommeligt Naupliusstadium. 
Bemerkninger. — Denne Familie er kun ba- 
seret paa en enkelt Slegt, Limnetis, som dog synes 
mig i saa mange vesentlige Punkter at afvige fra 
de til foregaaende Familie henregnede Slegter, at 
den fortjener at udskilles fra samme. Af Packard 
er den ogsaa opstillet som 'Typen for den ene af de 
2 Underfamilier, hvori hans Familie Limnadiade 
deles. Det fortjener dog her at nevnes, at den til 
foregaaende Familie horende Slegt Cyclestheria i 
visse Forhold synes at vise en Tilnermelse til neer- 
verende Familie, uden at den dog kan henregnes 
til samme. 
Gen. Limnetis, Lovén, 1846. 
Syn. Hedessa Liévin. 
Slegtscharacter. — Skallen mere eller mindre 
kugleformig, glat, uden tydelige Umboner. ‘Hovedet 
kjolet efter Midten og forleenget til et hos Hunnen 
mere eller mindre tilspidset, hos Hannen tveert af- 
kuttet Rostrum; til Siderne af Hovedet en vel ud- 
viklet bueformig Fornix. Haledelen meget liden, 
ikke omboiet og uden tandede Plader, men dekket 
nedenunder af en operkelformig Lamelle. Umiddel- 
bart foran den hos Hunnen 2 fra den dorsale Flade 
af Truncus udgaaende bladformige Plader. De sam- 
mensatte Mie sammensmeltede i Midten. Det enkle 
Mie vel udviklet, beliggende ner. de sammensatte 
Mine. Foran dem 2 tet sammenstillede cilierede 
Feldter. iste Par Folere kolleformige; 2det Par 
med Grenene neppe lengere end Skaftet og delte i 
talrige korte Led, hvert kun berende en enkelt 
Sveommeberste i Bagkanten. Overleben simpel, uden 
nogen tentakelformig Fortsats. 2det Par Kjever 
Fam. Limnetide. 
Characters. — Shell very tumid; the valves 
without lines of growth, and connected dorsally by 
an imperfect hinge. Head of enormous size, ending in 
a downward-curved rostrum of a different form in the 
two sexes. Trunk comparatively short and massive; 
tail, rudimentary. First pair of antenne small and 
simple; 2nd pair comparatively short, but powerful. 
The ‘masticatory part of the mandibles bluntly den- 
tated. Second pair of maxille rudimentary. Num- 
ber of legs not exceeding 12 pairs; the outer endites 
digitiformly produced; only the 1st pair in the male 
prehensile. Propagation markedly bi-sexual. Deve- 
lopment a complicated metamorphosis, beginning 
with a peculiar nauplius stage. 
Remarks. — This family is based upon only a 
single genus, Limnetis, which yet seems to me to 
differ in so many essential points from the genera be- 
longing to the foregoing family, that it merits being 
separated from them. It has also been established 
by Packard as the type of one of the 2 sub-families, 
into which his family Limnadiade is divided. It is, 
however, deserving of mention here that the genus 
Cyclestheria, belonging to the foregoing family, seems, 
in certain points, to approach the present family, 
though it cannot be classed under it. 
Gen. Limnetis, Lovén, 1846. 
Syn. Hedessa Liévin. 
Generic Characters. — Shell more or less sphe- 
rical, smooth, and without distinct umbones. Head 
carinated medially, and produced in the female to a 
more or less pointed rostrum, in the male to one 
abruptly truncated; at the sides of the head a well- 
developed arcuate fornix. Caudal part very small, 
not bent downwards, and without dentated lamelle, 
but covered beneath by an opercular lamella. Imme- 
diately in front of it in the female, there are two 
foliate lamelle issuing from the dorsal surface of 
the trunk. The compound eyes merged together in 
the middle. Ocellus well-developed, situated near 
the compound eyes. In front of them two juxta- 
posed, ciliated fields. First pair of antenne cla- 
vate; 2nd pair with the rami scarcely longer 
than the scape, the former composed of numerous 
short joints, each carrying only a single natatory 
bristle on the hind margin. Labrum simple, without 
