73 



er utydeligt tredelt og liar i den indre Kant en fin 

 Ciliering (Fig. 9). 



Bag Kindbakkerne folger nu tæt sammen de 

 ovrige Munddele (se Tab. XII, Fig. 1), som det ikke 

 er saa ganske let at isolere, da de delvis er for- 

 bundne ved et System af stærke Chitiulister. Imid- 

 lertid er det ikke saa vanskeligt at paavise, at de 

 danner '6 paa liinanden følgende Rækker: forrest en 

 vel udviklet Underlæbe, derefter 2 Par normalt iid- 

 viklede Kjæver. 



Underlæben (Fig. 10, 1, Fig. 11) bestaar af 2 

 symetriske Halvdele eller Lappe, forbundne i Midten 

 ved en tynd Membran. Enhver Sidelap er støttet 

 af en noget bueformig Cliitinplade, der ved Basis 

 hænger sammen med den tilsvarende forreste Kjæve 

 (se Fig. 10), og hvis Ende danner en smalt afrundet 

 indboiet Lob besat med tætte Haar. Indad fort- 

 sætter Chitinpladen sig i en tyndere, halvt mem- 

 branes Lamelle, der ligeledes er fint haaret i den 

 indre Kant og længere bagtil har et tæt tværstribet 

 marginalt Parti. Af andre Forskere er Underlæbens 

 Sidelappe tydede som Iste Kjævepar, hvad der 

 aabenbart er urigtigt, da disse Lappe er fuldstændig 

 nbevægelige og desviden forbundne i Midten ved en 

 tydelig Membran. Mærkelig er iethvertfald hos nær- 

 værende Gruppe Tilstedeværelsen af en vel udviklet 

 Underlæbe, som hos de høiere Crustaceer. Tlii hos 

 andre Phyllopoder, ligesom ogsaa hos den store Fler- 

 lied af Entomostraeeer, sees neppe enAnt_ydning til 

 denne Del. 



Iste Par Kjæver (Fig. 10 m\ Fig. 12) danner 

 hver en i Enden oxeformigt ndvidet Chitinplade, der 

 med sin tilspidsede Basis er forbunden med Under- 

 læbens Chitinskelet, og derfor ved Dissection ial- 

 mindelighed faaes i Samraenhæng med Undeidæben. 

 Paa (Irund af Cliitinsubstantsens Elasticitet kan de 

 imidlertid til en vis Grad bevæges imod hinanden, 

 og en Del tydelige Muskler, der lober skraat indad, 

 besorger denne enkle Bevægelse. Paa den øxe- 

 formigt udvidede indre Ende er de bevæbnede med 

 talrige korte Pigge og en hel Del stive Bor.ster. 

 Det forreste Hjorue danner en særskilt, noget paa- 

 tvært stillet Lap, som er forsynet med en Del noget 

 stærkere Pigge. 



2det Par Kjæver (Fig. 1, m -, Fig. 13), der af 

 andre For.skere (Packard) feilagtigt er tydede som 

 et Slags Kjævef odder, er af mere membranos Be- 

 skafienhed og ender indad med en afrundet, tunge- 

 formig Tyggela]5, besat med talrige grovt cilierede 

 Borster. Paa den ydre Side findes en stumpt conisk 

 Udvidning af en noget lignende spongiøs Beskatfen- 

 hed som Foddernes Epipoditer. Denne Udvidning 

 maa nærmest opfattes som et Slags rudimentær 

 Palpe. 



Fodderne er, som ovenfor nævnt, overordentlig 

 talrige, idet der paa den bagre Del af Truncus 

 (Metasome) findes mange flere Fodpar end der er 



10 — G, 0. Sårs: Fauna Noi^egiæ. 



The innermost tooth is faintly tripartite, and is 

 finely ciliated on its inner edge (fig. 9). 



The remainder of the oral parts now follow 

 closely behind the mandibles (see PI. XII, tig. 1), 

 and are not very easy to separate from one ano- 

 ther, being jiartially connected by a .system of 

 strong chitinous fillets. It is not, however, difficult 

 to see that they form 3 consecutive series: in front, 

 a well-developed inferior lip, and then 2 pairs of 

 normally-developed maxillæ. 



The inferior lip (figs. 10, 1, 11) consists of 2 sym- 

 metrical halves or lobes, connected in the middle 

 by a thin membrane. Each lobe is supported by a 

 somewhat arched chitinous lamella which is united 

 at the base to the corresponding anterior maxilla 

 (see fig. 10), and whose end forms a narrowly 

 rounded, incurved, thickly ciliated lobe. The chiti- 

 nous lamella is continued inwards in the form of a 

 thinner, half-membranous lamina also finely ciliated 

 on the inner edge, and whose marginal part, farther 

 back, is thickly barred transversely. The lateral 

 lobes of the lower lip are designated by other na- 

 turalists as the first pair of maxillæ, but this is 

 clearlv incorrect, as these lobes are quite immo- 

 vable, and are connected in the middle by a distinct 

 membrane. The presence, in this group, of a well- 

 developed inferior lip, as in the higher Crustacea 

 is, at all events, remarkable; for in other Phyllo- 

 poda, as also in the majority of Entomostraca, there 

 is scarcely an indication of this part. 



Each of the first pair of maxillæ (figs. 10 m', fig. 

 12) has the form of a securiformly expanded chitinous 

 lamella, which is connected by its pointed base with 

 the chitine skeleton of the inferior lip, and is there- 

 fore, when dissected, generally detached in conjunc- 

 tion with that part. On account of the elasticity of 

 the chitine however, they can, to a certain extent, be 

 moved towards one another, and several distinct 

 muscles, running obliquely inwards, eflPect this simple 

 movement. On the securiformly expanded inner end, 

 the maxillæ are armed with numerous short spines, 

 and a number of stiff bristles. The foremost corner 

 is in the form of a peculiar, somewhat obliquely- 

 placed lobe, furnished with a few stronger .spines. 



The second pair of maxillæ (fig. 1 m''', fig. 13) 

 which have been incorrectly interpreted by other 

 naturalists (Packard) as a sort of maxilliped, are of 

 a more membranous nature, and terminate inside 

 with a rounded linguiform masticatory lobe, clothed 

 with numerous coarsely ciliated bristles. On the 

 outer side, there is a bluntly conical expansion 

 of a spongy nature, somewhat similar to that of 

 the epipodites of the legs. This expansion should 

 probably be regarded as a sort of rudimentary palp. 

 The legs, as stated above, are remarkably 

 numerous, there being on the posterior part of the 

 trunk (the metasome), many more pairs of legs 



