105 



tydeligt sondrede, idet der mellem dem ogsaa dor- 

 salt er en temmelig dyb Indbugtning. Hovedet er 

 jævnt iivielvet oventil og afrundet fertil, med et 

 stnmpt Fremspring nedenfor det enkle Øie, forestil- 

 lende Anlægget til Rostrum. Umiddelbart bag dette 

 Fremspring sees de endnu knudeformige Iste Par 

 Folere at udgaa. Bag disse igjen rager den enormt 

 udviklede Overlæbe frem, med sin skraat nedad- 

 rettede pigformige Endefortsats. Ved dennes Basis 

 er der indad eii liden cilieret Lap, der sædvanligvis 

 er bcjiet ind mod ilnndaabningen og som svarer til 

 den verticalt stillede Endelamelle hos det voxue 

 l>yr. Til hver Side af Mnndaabningen sees de nu 

 vel udviklede Kindbakker, fra hvis ydre Side Man- 

 dibularfodderne iidgaar, og umiddelbart bag dem 

 igjen viser sig Anlægget til de 2 Par Kjæver. Ryg- 

 skjoldet har nu udviklet sig til en kappeformig 

 Huddnplieatur, bestaaende af 2 symetriske Halvdele 

 skilte Ijagtil i Midten ved en dyb Indbugtning. 

 Det har nu tvdeligt sondret sig ogsaa fortil; men 

 de 2 Halvdele gaar ganske umærkeligt over i hin- 

 anden dorsalt, uden at der endnu er nogen tydelig 

 Sondring af 2 Yalvler. De sig iidviklende Fodder, 

 der nu fuldstændig dækkes oventil a f Rygskjoldet, 

 har fdrlænget sig til noget polseiormige Fortsatsei", 

 der er rettede skraat bagtil og ligger tæt sammen, 

 Den bagerste I)el af Kroppen er ganske svagt om- 

 boiet mod Bugsiden og begynder at sondre sig som 

 en tydelig Haledel. I)e terminale Fortsatser viser 

 sig nu klarlig at være identiske med de senere be- 

 vægeligt til Enden af Haledelen indleddede Hale- 

 klor. I nogen Afstand fra dem paal)orsalsiden har 

 allerede Haleborsterne udviklet sig; derimod er der 

 endnu ikke noget Spor af de for det voxne Dyr 

 charaeteristiske taiulede Hale]ilader. Af de For- 

 andringer, der er foregaaet med den indre Organi- 

 sation kan nævnes, at de i tidligere Stadier simple 

 iDlindsækformige Udvidninger af Tarmens forreste 

 Del har hver sondret sig i en dorsal og en ventral 

 La]), og at Hjertet har dannet sig i den forreste 

 Del af Truncus. 



Sidste Larvestadium er fremstillet Fig. 7. fra 

 Rygsiden. Legemet har nu en Længde af 1,1-1: mm. 

 og ligner idethele samme hos de 2 foregaaende Sta- 

 dier, dog med den Forskjel, at Hovedets Pandedel 

 er noget mere fremspringende, og at Rygskjoldet 

 er betydelig storre. Dette sidste dækker nu som 

 en lired Ka])pe. Størsteparten af Truncus tilligemed 

 de til samme horende Lemmer oventil og har bagtil 

 et dybt Indsnit. Fodderne, hvis Antal fremdeles 

 kun er 6 Par, er endnu fuldstændig ubevægelige, 

 men har nu sondret sig i sine respective Hoved- 

 afsnit, hvoraf navnlig Epipoditerne er meget tyde- 

 lige i Dyrets dorsale Stilling. Fra Enderne af Fod- 

 derne er allerede korte Bor.ster begyndt at spire 



U — 6. 0. Sårs: Fauna Sorvegix. 



very distinctly defined, as there is, dorsally too, a 

 rather deep hollow between them. The head i.s 

 evenly arched above and rounded in front, with a 

 Idunt projection below the ocellus, representing the 

 riidimeut of the rostrum. Immediately liehind this 

 projection, the still nodiform 1st jiair of antennæ 

 are seen to issue. Behind them again, projects the 

 enormously developed labrum, with its spiniform 

 terminal protuberance directed obli([uely downwards. 

 At its base inside, there is a little ciliated lol.ie, 

 which is usually bent in towards the oral aperture, 

 and which eorres])onds to the vertically-placed ter- 

 minal lamella in the full-grown animal. ()n earh 

 side of the oral aperture are seen the now well- 

 developed mandibles, from the outer side of which 

 issue the mandibular legs, and immediately liehind 

 tliem again, ajjpear the rudiments of the 2 pairs of 

 nmxillæ. The carapace has now developed into a 

 hdod-shaped cuticular duplicature, consisting of 2 sym- 

 metrical Jialves, separated behind in the middle lay a 

 deep dejiression. It has also become well defined 

 in front, but dorsall\' the two halves run ([uite 

 imperceptil)ly into one another, without as yet any 

 distinct division into 2 valves. The developing legs, 

 whi(,'li are now completely covered above by the 

 cara]iace, have lengthened into somewhat sausage- 

 shaped protuberances, directed obliquely backwards, 

 and lymg close together. The hinder part of the 

 bodj' is very slightly bent down to\\-ards the ventral 

 surface, and begins to be marked otf as a distinct 

 caudal part. The terminal jtrojections now .show 

 themselves clearly to be identical with the caudal 

 claws suljseqi^ently mova1>ly articulated to the end 

 of the caiidal section. At some distance from them 

 on the dorsal side, the caudal bristles have already 

 developed, whereas there is as yet no trace of the 

 dentated caudal lamellæ characteristic of the adult 

 animal. Among the changes that have occurred in 

 the internal organisation, it may lie mentioned that 

 the simple cæcal expansions of the front part of the 

 intestine in earlier stages, have become marked otf 

 into a dorsal and a ventral lobe, and that the heart 

 has lieen formed in the anterior ])art of the trunk. 

 In fig. 7, the last larval stage is represented, 

 seen from the ventral surface. The liody now has 

 a length of 1,14 mm., and on tiie whole resembles 

 that in the 2 preceding stages, though with these 

 dirtereuces, viz.. tliat the frontal part of the head 

 is rather more prominent, and that the carapace is 

 considerably larger. The latter now covers like a 

 broad mantle the upper pfirtion of the greater part 

 of the trunk and limbs, and has a deep emargina- 

 tion liehind. The legs, which still only number <i 

 pairs, are as yet (^uite immovable, but are now divided 

 into their respective principal parts, of which no- 

 tably the epipodites are very distinct in the ani- 

 mal's dorsal position. From the extremities of the 



