Subordo II. 



PHYLLOPODA. 



Character. Branchiopoder af meget foi skjellig 

 Kropsform, dels uden, dels med Rygskjold, det sidste 

 undertiden udviklet i Form af 2 voluminøse, det 

 hele Dyr omsluttende Valvler. Legemets Segmenta- 

 tion forskjellig hos de forskjellige Former. Øinene dels 

 stilkede, dels sessile, imdertiden næsten sammensmel- 

 tede; et mediant Enkeltoie (^ocellus) tilstede. Følerne 

 i Regelen meget ulige udviklede; Iste Par som oftest 

 meget smaa og udelukkende sensitive; 2det Par 

 af forskjellig Bygning, snart rudimentære (hos det 

 voxne Dyr), snart udviklede til kraftige 2grenede 

 Aarer, eller til tangformige Griberedskaber (hos- 

 Hannen). Overlæben vel udviklet, klapformig; Under- 

 læben i Regelen manglende. Kindbakkerne hos det 

 udviklede Dyr uden Palpe. To Par Kjæver tilstede, 

 begge smaa og af forholdsvis simpel Bygning. Alle 

 bag Munddelene følgende Lemmer respiratoriske, af 

 tilnærmelsesvis uniform Bygning og bladdannet lap- 

 pet Form; deres Tal meget forskjelligt, undertiden 

 abnormt stort. Udviklingen i Regelen en corapli- 

 ceret Metamorphose, begyndende med et frit Nauplius- 

 Stadium. Indlandsdyr. 



Bemærkninger. Denne Underorden omfatter et 

 ikke meget stort Antal Dyreformer, der imidlertid 

 viser meget væsentligeForskjelligheder, saavel hvad 

 det ydre TJdaeende som den indre Bygning angaar. 

 Hvad der hovedsageligt characteriserer denne Af- 

 deling af Branchiopoder, og har givet dem sit Navn, 

 er Structuren af de bag Munddelene følgende Lem- 

 mer, der alle viser et lignende bladfoi'migt og lappet 

 Udseende som de til Midtkroppen hos Phyllocariderne 

 horende saakaldte Branchialfødder. Da de tillige i 

 sin Function er ndpræget respiratoriske, benævnes 



Sudorclo IL 



PHYLLOPODA. 



Characters. Branchiopods of very various 

 shape, partly without and partly with carapace, 

 the lastnamed sometimes developed in the form of 

 2 voluminous valves enveloping the entire animal. 

 The segmentation of the body difierent in the 

 various forms. Eyes partly pedunculated, partly 

 sessile, sometimes nearly coalescent; a median single 

 eye (ocellus) present. Antennæ, as a rule, very 

 unequally developed; 1st pair most frequently very 

 small and exclusively sensitory; 2nd pair of vari- 

 able structure, sometimes rudimentary (in the adult 

 animal), sometimes developed to powerful, 2-branched 

 oars, or to pincer-.shaped prehensile apparatus (in 

 the male). Antez'ior lip well developed, flap-formed; 

 posterior lip, as a rule, wanting. Mandibles, in the 

 developed animal devoid of palpi. Two pairs of max- 

 illæ present, both small and of relatively .simple 

 structure. All the apjiendages placed behind the 

 oral parts respiratory, of approximately uniform 

 structure and leaf-formed shape; their number very 

 variable, sometimes abnormally large. The de- 

 velopment usually a complicated metamorphosis, 

 commencing with a free Nauplius-stage. Inland 

 animals. 



Remarks. This sub-order includes a not very 

 large number of animal forms, which exhibit, how- 

 ever, very material divergencies, both in respect of 

 the external appearance as well as in the internal 

 structure. What chiefly characterizes this division of 

 Branchiopods and has gevin to it its designation is, 

 the structure of the appendages placed behind the 

 oral parts, wliich all exhibit a similar leaf-shaped 

 and lobed appearance as the so-called branchial-feet 

 pertaining to the mesosome in the Phyllocarida. 

 As they are, besides, in their function prominently 



