107 



rundet Form, med den ovre Kant, livor ^'alvlerne 

 stoder sammen, næsten ret og endende saavel fortil 

 som bagtil med et tvdeligt frems])ringpiide Hjorne. 

 (Jvenfra seet (se Fig. S) viser den sig temmelig 

 buget, idet Breden næsten er lig Hoiden. Til hver 

 Side sees Skalkjertelen med den umiddelbart foran 

 samme liggende Muskelarea med stor Tvdelighed, 

 og paa G-rund af Skallens store Gjennemsigtiglied 

 træder ogsaa den af samme bedækkede Del af Lege- 

 met klart og tydeligt frem. Man kan nu paa Lege- 

 met ad.sldlle alle de Afsnit, som ovenfor er beskrevet 

 hos det voxne Dyr. Dog er Xakkesegmentet endnu 

 temmelig kort, og Truncus kun lidet længere end 

 det forreste Afsnit af Legemet. Hovedet har en 

 fra samme hos det voxne Dyr temmelig afvigende 

 Form. Dets ovre Flade er noget uregelmæssigt 

 hvælvet og endnu iiden Spor af det characteristiske 

 stilkede Fastheftniiigsorgan, som forst senere dan- 

 nes ved en gradvis Afsnoring af en Del af Hovedets 

 Dorsalparti. Pandedelen er endnu kun lidet frem- 

 springende, og mellem den og det stumjit tilrundede 

 Rostrum er der neppe engang den svageste Indbugt- 

 ning at se. Af Hovedets Yedhæng er Iste Par Fo- 

 lere lidt mere forlængede end hos Larverne, men 

 endnu forholdsvis smaa og uden laterale Lappe. 

 2det Par Folere, eller Aarerne, har, som ovenfor 

 anført, tabt baade den bagudbøiede Borste ved Enden 

 af Skaftet og den tvedelte basale Fortsats. For- 

 ovrigt stemmer de, saavel hvad Skaftets som Gre- 

 nenes Bygning angaar, temmelig nær overens med 

 samme hos Larverne, alene med den Forskjel, at 

 der i Yderkanten af den ovre Gren har udviklet sig 

 en kort Pig, livoraf intet Spor var at se Ims hine. 

 Overlæhen er nu betydelig redueeret i Storrelse og 

 har antaget det for det voxne Dyr characteristi.ske 

 Udseende, idet den lange, dolkformige Endedel er 

 svundet ind til en forholdsvis Iiden tentakelformig 

 Fortsats. Paa Kindbakkerne er der endnu igjen et 

 Hudiment af Mandibulai'fodderne i Form af et til 

 deres Yderside fæstet ubetydeligt koniskt Appendix 

 uden Spor af Leddeling eller Borstebesætning. Bag 

 Kindbakkerne sees de 2 Par Kjæver, son^ nu, lige- 

 soin Kiiidliakkerne, er i fuld Virks(}mlie(l med at 

 bearbei(h' den optagne Nan-ing. De hos Lar\en an- 

 lagte (i Pai' Branchialfodder er nu funetioiisma-ssigt 

 udviklede, lulforende sine characteristiske svingende 

 Bcvægelser for Kespirationens og Næringso])tagel- 

 sens Formaal, og bag d(>m er dei- endnu .Anlæg 

 til .") eller 4 1'ar nye Fodder, llalcdcli-n er endnu 

 kun svagt omlioiet og Haleklorne utuldsta-ndigt son- 

 drede fra Haleemlen. i)e liar h\er luer Basis en 

 enkelt kort Sidetand, og nmi<ldelbart ovenfor dem 

 udgaai- fra Halens D(n'salsi(h' 2 meget smaa jevn- 

 sides stillede l''renispring, som forestiller det forste 

 .\iilicg til de tandede Halejjladcr. Ovent'or Halc- 

 borsterne har (Kt endvidere udviklet sig et enkelt 

 Par af de hos det voxne Dvr her forekommende 



valves meet, almost straight, and ending both in 

 front and behind in a distinctly projecting corner- 

 Seen from above (see fig. 8), it appears rather 

 bulging, its breadth being almost eijnal to its 

 height. On each side is seen the shell-gland very 

 distinctly, with the muscular area lying immediately 

 in front of it; and on account of the great trans- 

 parency of the shell, that part of the body which 

 it cover.s is seen very clearly and distinctly. All 

 the sections of the l)ody described above in the 

 adult animal, can now Ije distinguished. The cervi- 

 cal segment, however, is still rather short, and the 

 trunk only a little longer than the foremost section 

 of the body. The head has a rather ditferent shajje 

 to that in the adult animal. Its upper surface is 

 somewhat irregularly arched, and still without a 

 trace of the characteristic stalked organ of attach- 

 ment, whicli is fornu'd, but not until later, by a 

 gradual constriction of a part of the dorsal regie ui 

 of the head. The frontal region still ])rojects imly 

 slighth-, and lietween it and the bluntly rounded 

 rostrum, there is scarcely even the slightest hollow 

 to be seen. Among the aj)i)endages of the head, 

 the first jiair of antennæ is a little more elongated 

 than in the larva, but still comparativeh' small 

 and without lateral lobes. Tiie 2nd pair of antennæ, 

 or the oars, have, as stated above, lost both the 

 backward-curved lu-istle at the end of the scape and 

 the bifid basal projection. Li other respects they 

 agree very closely, as regards the structure of both 

 the scape and the rami, with those limbs in the 

 larva, with the one ditferenee that in the outer 

 margin of the up])er ramus a short spike has deve- 

 loped, of which there was no trace in the larva. 

 The labrum is now considerably reduced in size, 

 and has assumed the appearance characteristic of 

 the adult animal, the long, ensiform terminal part 

 having shrunk into a comjiaratively snuill, tenta- 

 cular projection. Tliere is still a rudiment of the 

 mandibular legs left on the nuuidibles in the form 

 of an indistinctly conical ap)>endage, — without a 

 trace of articulation or bristles, — attached to their 

 outer side. Behind the mandibles are seen the 2 

 pairs of maxilke, which now, like the mandil)les, 

 are in full activity, uKinipulating tlie food admitted. 

 The (■) pairs of branchial legs commenced in the 

 larval stage are now able to ])erform their function, 

 executing theii- charactcristit' swinging movements 

 for the ]iur])ose of respiration and the admission of 

 food; and there are the rudiments of o or 4 pairs 

 of new legs. The caudal ])art is still only .-^lightly 

 bent down, and the caudal claws im|)erfectly nmrked 

 olf from tiie end of tlie tail. They each have near 

 the base a single, sluirt, lateral tooth, and inunc- 

 (liatelv above them, there issue from Ibe dorsal 

 side of the tail 2 very suu\ll juxta])osed ])rojections, 

 representing the earliest rudiment of the dentated 



