93 



Spor ilt' taiidformige Fremspring. Fdnuleu de kraf- 

 tige Addnctormiiskler, der fylder Storsteparten af 

 den indre HiiUied at' Corpus, sees ogsaa en Del 

 andre Muskler at passere til Kindbakkenie, ved 

 Hjælp af hvilke disse kan dreies om sin Axe inden 

 visse Gi'ændser. I)e stærkeste af disse Ivotations- 

 niiiskler ndspringer fra den dorsale Flade af Xakk(*- 

 segmentet og convergerer mod Kindbakkernes bagre 

 Side (se Fig. 2). Nogle betydelig mindre j\[uskler 

 passerer fra Hovedets dorsale Integument til For- 

 siden af Kindl)akkerne. 



Xogen Underlæbe har det ikke lykkets mig at 

 ])aavise. Prof. Lilljeborg tror dog at lia\e fundet 

 den i Form af 2 meget smaa tilspidsede og tæt baa- 

 rede Lappe. 



Første Par Kjæver (Fig- -' 'i' •'• '" '• ^'^ig- 1") 

 bestaar af en kort og tyk Basaldel og en meget 

 bevægelig indadboiet, skiveformig Endedel, der jjaa 

 sin frie Rand er besat med en tæt Kad af tynde, 

 ieformigt krummede Boi'ster, alle t\'deligt 2-leddede 

 og tint eilierede. Foruden dem tindes der endnu en 

 IJad af betydelig kortere Bor.ster eller Pigge, der er 

 grovt taiulede i Kanterne og ender i en særdeles fin 

 og delicat Sp>ids (se Fig. 11). Disse Børster er dog 

 kun indskrænkede til den bagre Halvdel af lianden. 

 Endelig bemærkes fort il, i Vinkelen mellem Basal- 

 delen og Endelamellen en meget liden, men tydeligt 

 begrændset, seeundær Lamella af smal tungedannet 

 Form og kantet med nogle gan.ske korte Borster. 



Andet Par Kjæver (Fig. 2, 4, Sl, ni-, Fig. 12, Ki) 

 er betydelig mindre end Iste Par og, som det synes, 

 kun lidet bevægelige. De bestaar ligeledes af en 

 kort Basaldel og en indadrettet Endelanudle af 

 elli])tisk Form, med det indre afrundi'(le lljorne be- 

 tydelig mere fremspringende end det ydvf. Lamellen 

 er kantet med omkring 24 tæt eilierede Borster, som 

 dog er utydeligt leddede og kun mod det iiulre 

 Hjørne naar nogen betydelig Længde. 



Af Fodder har jeg hus tiildt udviklede Individer 

 talt 22—2:5 P;ir. Prof. Lilljeborg har hos ualmin- 

 delig store Exemplarer endnu fundet et Par bag 

 di.sse, saa at deres Tal kan stige til 24 Par ialt; ja 

 (^I'ube paastaar endog hos et Individ at have talt 

 26 Par. De er idethele af en meget uniform Byg- 

 ning og viser alle Charaeteren af a^gte Branc'hial- 

 fodder. Foruden til lIes])iration, hai- de imidlertid 

 ogsaa en væsentlig Betydning ved Xa'ringso])tagel- 

 sen, idet de i Våndet værendi» organiske Smaadele, 

 hvoraf Dyret nærer sig, ved Foddernes rhytniiske 

 Bevægelser bliver hvirvlet ind mod Mundilelene. 

 De 10 eller 11 forreste Par er nogenlunde af samme 

 Længde, men fra det Ilte Par begynder de stærkt 

 at aftage i Storrelse, og de allerbagerste Par er 

 overmaade smaa og vanskeliir at tælle. D-^ har alle 



broad, tinely-tluted molar surface without a trace of 

 dentate projections. Besides the powerful adductor 

 muscdes, which fill the greater part of the inner 

 cavity of the body, a few other muscles are also 

 seen passing to the mandibles, which, by their aid, 

 can turn upon their axis within certain limits. The 

 sti'ongest of these rotator}- muscles issue from the 

 dorsal surface of the cervical segment, and converge 

 toward.s the posterior side of the mandibles (see 

 fig. 2). Some much smaller muscles jiass from the 

 dorsal integument of the head to the anterior side 

 of tlie mandibles. 



1 have not succeeded in proving the presence 

 of any jKjsterior lip. Prof. liilljeborg, however, be- 

 lieves that he has found it in the shape of two very 

 small, ]iointed, and densely hairy lobes. 



The tirst pair of niaxillæ (figs. 2, 4, 9, ;«'. fig. 

 10) consist of a short and thick basal jjart, and a 

 very movable, incurved, lamellar, terminal part, 

 which is clothed on its free margin with a (dose 

 row of thin, falciformly curved bristles, all distinctly 

 2-jointed and finely ciliated. In addition to these, 

 there is yet another row of much shorter bristles 

 or spines, which are coarsely dentated at the edges, 

 and end in a piarticularly fine and delicate point 

 (see fig. 11). These bristles, however, are only con- 

 fined to the posterior half of the margin. Lastly, 

 thei'e is visible in front, in the angle between the 

 basal part and the terminal lanifdla. a very small, 

 but distinctly defined lamella, of a narrow lingular 

 f(jrm. ami edged with a few very short bristles. 



The 2nd pair of maxillæ (rigs. 2, 4. 9, w-, figs. 

 12, 13) are considerabl\- smaller than tiie first pair, 

 ami a])]iarently (nily slightly movable. Tiiey also 

 consist of a siiort basal part, and an inward-direc- 

 ted terminal lamella of (dliptical sha|)e, with the 

 inner rounded corner considerably more prominent 

 than the outer one. The lamella is bordered with 

 about 24 thi(d<ly ciliated bristles, which are iiow- 

 ever, indistinctly articulated, and only at the inner 

 corner attain any considerable length. 



In fully develo])ed animals, I have counted from 

 22 to 2o pairs of legs. I'rof. Lilljeborg has even 

 found a pair behind these in unusually large speci- 

 mens, so that their numl)er can rise to 24 pairs in 

 all; indeed, (irube asserts tliat in one specimen he 

 has counted as many as 2() pairs. They are, on 

 the whole, of a very uniform structure, and exhibit 

 all the characters of true branchial legs. They are, 

 however, of essential inqiortance, not only in respi- 

 ration, but also in tlie admission of nourishment, as 

 the organic jiarticles in the water, on which the 

 animal feeds, are whiided in towards the oral parts 

 by the rhythmical movements of the legs. Tlie 10 

 or 1 1 foremost ]iaii"s are of about e(pial length, but 

 after the Iltii pair they begin to diminish rapidly. 

 the hindmost jiairs being exceedingly small and 



