Fam. Apodide. 
Character: — Mbypesbiolaet bredt afrundet fortil, 
 fladt hvelvet, og indskaaret bagtil, med en tydelig 
transversal Nakkefure, begrendsende Hovedet. bag- 
til; det sidste.skovlformet, visende en halvmaane- 
_ formig ventral Duplicatur, bag hvilken Folere og 
Munddele har sin Plads. Den bagre Del af Lege- 
met mere eller mindre fremragende bag Rygskjoldet 
og delt i talrige korte, med fine Torne omkrandsede 
_ Segmenter. Haletraadene sterkt forlengede. Over- 
leben bred, klapformig; Underleben  tvekloftet. 
Wy Kindbakkerne med grovt tandet Eg. iste Par Kje- 
_ ver oxeformige; 2det Par med en membrangs lateral 
 Fortsats. Alle Fodder med tydeligt begrendset 
Be isinap: Iste Par mere eller mindre ulige de 
_ ovrige, med Enditerne traadformige; de nest fol- 
gende Par prehensile, med Enditerne delvis klo- 
_ formige; 11te Par hos Hunnen med Epi- og Exopo- 
 diten omformede til en kapselformig Mgbeholder. 
_ Hannerne meget sjeldne, betydelig mindre end Hun- 
__nerne, og uden specielle prehensile Organer. 
Bemerkninger. — Denne Familie indeholder 
kun 2 Slegter, Apus og Lepidurus, der staar hin- 
anden overmaade ner, og begge har en meget vid 
I aieiphick Udbredning, idet de er representerede 
_baade i den nye og gamle Verden, ligesom ogsaa 
i Australien. Kun den sidste af disse Slegter er 
repreesenteret i vor Fauna. 
Gen. Lepidurus, Leach, 1816. 
___- Slagtscharacter. — Rygskjoldet ialmindelighed 
_ meget stort, dekkende den storste Del af Kroppen 
, forsynet bagti] med en mere eller mindre ud- 
langsgaaende dorsal Kjol. Sidste Haleseg- 
forlenget mellem Haletraadene til en plade- 
Udvidning. 1ste Fodpar med Enditerne for- 
-korte, kun lidet overragende Rygskjoldets 
. 63 Fodpar tilstede. Forovrigt overensstem- 
med. Een Apus. 
per. — Den her omhandlede Slegt 
ms af den bekjendte Naturforsker 
entlig characteriseret ved Tilstede- 
median Haleplade, der ganske mang- 
t ved de forholdsvis korte Enditer 
Da midlertid forovrigt de herhen 
, det noieste stemmer overens med 
bitus som i de anatomiske 
67 
Fam. Apodide. 
Characters. — Carapace broadly rounded in 
front, slightly vaulted and indented behind, with a 
distinct transverse cervical furrow defining the head 
posteriorly; the latter shovel-formed and exhibiting 
a crescent-shaped ventral duplicature, behind which 
the antenne and oral parts are situated. Hind part 
of the body projecting more or less behind the cara- 
pace, and divided into numerous segments, encircled 
by fine spikes. Caudal filaments very much elong- 
ated. Anterior lip broad and flap-like; posterior lip 
bifid. Mandibles with the cutting edge coarsely den- 
tated. First pair of maxille securiform, second pair 
with a membranous lateral expansion. All the legs 
with clearly defined coxal lobes; first pair more or 
less unlike the remainder, with the endites filiform; 
the next pairs prehensile, with the endites partially 
claw-like; 11th pair in the female, with the epipo- 
dite and exopodite transformed into a capsular ovi- 
sac. Males very rare, considerably smaller than 
the females, and without special prehensile organs. 
Remarks. — This family contains only two 
genera, Apus and Lepidurus, which are very nearly 
allied, and both have a very wide geographical dis- 
tribution, being represented both in the old and the 
new world, as also in Australia. Only the latter 
of these two genera is represented among the Nor- 
wegian fauna. 
Gen. Lepidurus, Leach, 1816. - 
Generic Characters. — Carapace usually- very 
large, covering the greater part of the body, and 
furnished posteriorly with a more or less marked 
longitudinal dorsal keel. Last caudal segment pro- 
longed between the caudal filaments to a lamellar 
expansion. First pair of legs with the endites com- 
paratively short and projecting only slightly be- 
yond the edge of the carapace. There are 63 pairs 
of legs. In other respects it agrees with the genus 
Apus. 
Remarks. — The genus here treated of was 
first established by the well-known English natu- 
ralist, Leach, and is characterised principally by 
the presence of a median caudal lamella, which is 
altogether absent in Apus, and by the comparatively 
short endites in the first pair of legs. As, however, 
the species belonging to this genus agree in other 
