73 



er ntycleligt tredelt oq; liar i den indre Kant en tiu 

 Ciliering iFig. 9 V 



Bag Kindluilvkerne folger nn tæt sammen de 

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

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

 bundne ved et System af stærke Cliitinlister. Imid- 

 lertid er det ikke saa vanskeligt at paavise, at de 

 danner 3 paa hinanden folgende Rækker: forrest en 

 vel ndviklet Underlæl)e, deretter 2 Par normalt ud- 

 viklede Kjæver. 



Tnderlæben iFig. 10, 1, Fig. 11) hestaar af 2 

 symetriske Halvdele eller Lappe, forlnindne i Midten 

 ved en tynd Membran. Enhver Sidelaji er stottet 

 af en noget bueformig Chitinplade, der ved Basi.s 

 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 niem- 

 branos Lamelle, der ligeledes er tint ha aret i den 

 indre Kant og længere liagtil har et tæt tværstribet 

 marginalt Parti. Af andre Forskere er Underlæbens 

 8idelappe tydede som Iste Kjævepar, hvad der 

 aabenbart er nrigtigt, da disse Lapjie er fuldstændig 

 ubevægelige og desuden forbundne i ilidten ^•ed en 

 tydelig Membran. Mærkelig er iethvertfald hos nær- 

 værende (irruppe Tilstedeværelsen af en vel ndviklet 

 Underlæbe, som hos de lioiere ("rustaceer. Thi hos 

 andre Phyllopoder, ligesom ogsaa hos den store Fler- 

 hed af Entomostraeeer, sees neppe en Antvdning til 

 denne Del. 



Iste Par Kjæver (Fig. 10 m ', Fig. 121 danner 

 hver en i Enden oxeformigt udvidet Chitinplade, der 

 med sin tilspidsede Basis er forbunden med Under- 

 læbens t'hitinskelet, og derfor ved Dissection ial- 

 mindelighed faaes i Sammenhæng med Underlæben. 

 Paa Grrnnd af Chitinsubstantsens Elasticitet kan de 

 imidlertid til en vis (xrad bevæges imod hinanden, 

 og en Del tydelige Muskler, der lober skraat indad, 

 Ijesorger denne enkle Bevægelse. Paa den oxe- 

 formigt udvidede indre Ende er de bevæbnede med 

 talrige korte Pigge og en hel Del stive Borster. 

 Det forreste Hjorne danner en særskilt, noget paa- 

 tvært .stillet Lap, som er forsvnet med en Del noget 

 stærkere Pigge. 



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

 andre Forskere (Packard) feilagtigt er tydede som 

 et Slags Kjævefodder, er af mere membranos Be- 

 skaftenhed og ender indad med en afrundet, tunge- 

 formig Tjrggelap, besat med talrige grovt cilierede 

 Borster. Paa den ydi-e Side findes en stumpt coni.sk 

 Udvidning af en noget lignende spongios Beskaifen- 

 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) tindes mange flere Fodpar end der er 



10 — G. 0. Sårs: Fauna Norv^fjia'. 



The innermost tooth is faintly tripartite, and is 

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



The remainder of the oral parts now follow 

 closel}^ behind the mandibles (see PI. XII, fig. 1), 

 and are not very easy to separate from one aii|i- 

 ther, being jiartially connected by a sy.stem 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 iiase to the corresjionding anterior maxilla 

 (see fig. 10), and wliose 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 fir.st pair of maxillæ, but this is 

 clearly 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 l)y 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 oblii[uely inwards, efi'ect this simple 

 movement. On the securiformly exjianded inner end, 

 the maxillæ are armed with numerous short .s])ines, 

 and a number of stitf In'istles. The foremost corner 

 is in the form of a peculiar, somewhat obli(]uely- 

 placed lobe, furnished v.'ith a few stronger spines. 



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

 which have been incorrectly interpreted l)y other 

 naturalists (Packard) as a sort of maxillijied. are of 

 a more membranous nature, and terminate inside 

 with a rounded linguiform masticatory lobe,- clothed 

 with niTmerous coarsely ciliated bristles. On the 

 outer side, there is a bluntly conical expansion 

 of a sjDongy nature, somewhat similar to that of 

 the epipodites of the legs. This exjiansion should 

 probably be regarded as a sort of rudimentar}^ palj). 



The legs, as stated above, are remarkably 

 numerous, there being on the posterior part of the 

 trunk (tlie metasome), many more ])airs of legs 



