130 



Fig. 19. 



Fig. 20. 

 Fig. 21. 



ganer; r Kectum; rr Bugretractorer; s, s Segmental- 

 organer;. sp Spiserør; t Tarmspiralen; ß contractiit Kar ; 

 n Nerve. 



Forreste Ende af Snabelen med Mundaabning og Ten- 

 takler. 



Hudlegeme, seet under svag Forstørrelse. 

 Gjennemsnit af Huden, 300 Gange forstørret, c, c, c Cuti- 

 cula; (2 cylindriske Celler; g, g compact Pigment; h,h,h 

 stjerneformigt Pigment; e Cuticularepithelet; r Ring- 

 muskler; Z Længdemuskler; f Udførselskanal for Hud- 

 legemet; p,p Peritoneum; a, a Hudlegemer» 



PHASCOLOSOMA SQÜAMATUM, Nobis. 

 (Tab. 13, Fig. 11. Tab. 14, Fig. 14-15.) 



Kroppen, omtr. 11 Mm. lang, er kølleformig; den ba- 

 gerste afrundede Ende er bredest, 3 Mm., — overalt tæt 

 besat med temmelig store, faste, flade, uregelmæssig for- 

 mede og ophøiede Skjæl. Imellem disse findes smaa 

 Sandpartikler (Quartskorn) tilheftede Huden ved et seigt 

 Slim. Analaabningen rund lige ved Snabelens Begyndelse. 

 Denne er 28 Mm. lang, halv gjennemsigtig og forsynet 

 med yderst fine Papiller, der staa langt fra hverandre i 

 Rækker, men blive tættere opimod Tentaklerne. Disse 

 ^re korte, traadformige, 8 i Antal. Huden er fast, tem- 

 melig tyk, seig og papilløs, bedækket paa dens indre Flade 

 med det sædvanlige Muskellag af Ring- og Længdefibre, 

 der ere beklædte af Peritoneum. Der findes kun én Re- 

 tractor, der tager sit Udspring fra Bunden af Kropshul- 

 heden med fire korte Rødder, og gaar saa fortil som en 

 rund, lige Søile midt igjennem Kropshulheden og Snabelen 

 for at fæste sig ved Grunden af Tentakelkrandsen. Spise- 

 røret ligger først omsluttet af Retractorens Fibre ved 

 deres Insertion; men kommer strax frem for, som et tyndt 

 Rør, at følge Retractoren til omtr. 5 Mm. fra dennes Ud- 

 spring. Nu udvides det betydeligt, idet det gaar over i 

 Tarmen, der paa høire Side af Retractor danner 5 løse, 

 lange Slyngninger, som ligge paalangs i Kropshulheden, 

 hvoraf den sidste Slynge naar næsten ned til Retrac- 

 torens Rødder; herfra stiger den under denne fortil langs 

 den venstre Side af Retractor omtr. % af Kropshul- 

 hedens Længde for med en skarp Bøining at gaa over i 

 den spiralformede Del af Tarmen, der ender i en lang, 

 temmelig smal Rectum (Fig. 14 re), som lige ved dens 

 Udmunding er fæstet til Huden ved et tyndt Muskelbundt. 

 Hvor Tarmen gaar over i Rectum findes en liden Diver- 

 tikel, der corresponderer med Tarmhulheden. Langs Spise- 

 røret, men fæstet til Snabelens indvendige Flade med et 

 Slags Mesenterium, findes et yderst tyndt, rørformigt, con- 

 tractiit Kar, der tager sin Begyndelse fra Tentakelkrand- 

 sen, og strækker sig lige ned til Snabelens Ende (læn- 

 gere kunde det ikke forfølges). Generationsorganet er 

 fæstet til Spiserøret og Tarmslyngerne og strækker sig 

 fortil opimod Segmentalorganet, og bagtil lige til Krops- 

 hulhedens Bund. Segmentalorganet har en Pæreform og 

 ligger til venstre Side af Retractor strax foran Tarmspi- 

 ralen. Nervestrengen gaar lige fra Bunden af Kropshul- 



Fig. 19. 



Fig. 20. 

 Fig. 21. 



serpentine organs; r rectum; rr ventral retractors* 



s, s segmental organs; sp oesophagus; t spiral of the 



intestine; h contractile vessel; n nerve. 



Anterior extremity of the proboscis with oral aperture 



and tentacles. 



Cuticular body, slightly magnified. 



Section of skin, magnified 300 times, c, c, c cuticula; 



d cylindrical cells; g,g compact pigment; e cuticular 



epithelium; r annular muscles; I longitudinal muscles; 



f excretory duct for the cuticular body; p, p peritoneum; 



a, a cuticular bodies; h,li,h radiated pigment. 



PHASCOLOSOMA SQÜAMATUM, Nobis. 

 (Tab. 13, fig. 11. Tab. 14, fig. 14—15.) 



The body, about 11 Mm. long, is claviform; the 

 posterior rounded extremity is broadest, 3 Mm., every- 

 where densely covered with rather large, firm, flat, irre- 

 gularly formed and elevated scales. Between these there 

 are found small particles of sand (grains of quarts) stuck 

 to the skin by a tough slime. The anal aperture round, 

 and close to the commencement of the proboscis. The 

 latter is 28 Mm. long, semi-transparent and furnished 

 with extremely fine papillæ, which are situated far from 

 each other in rows, but become more closely placed 

 towards the tentacles. These are short filiform 8 in 

 number. The skin is firm, rather thick, tough and with 

 papillæ, lined on its inner side with the usual muscular 

 layer of annular and longitudinal fibres covered by the 

 peritoneum. There is only one retractor, which takes 

 its issue from the bottom of the perivisceral cavity with 

 4 short roots, and goes then forward, like a round straight 

 column, through the middle of the perivisceral cavity and 

 the proboscis, attaching itself at the base of the tentacu- 

 lar circlet. The oesophagus lies at first surrounded by 

 the fibres of the retractor at their insertion, but soon 

 comes out, and, like a thin tube, accompanies the re- 

 tractor to within about 5 Mm. of its source. Now it is 

 extended considerably, going over into the intestine, which 

 on the right side of the retractor forms 5 loose long 

 slings lying lengthwise in the perivisceral cavity, and of 

 which the last sling extends nearly to the roots of the 

 retractor; hence it rises under the latter, forward along 

 the left side of the retractor, about % of the length of 

 the perivisceral cavity, going over with a sharp turn into 

 the spiral part of the intestine which ends in a long 

 rather narrow rectum (fig. 14 re), attached, close to its 

 orifice, to the skin by a thin fascicle of muscles. Where 

 the intestine goes over into the rectum, there is a little 

 diverticle corresponding with the cavity of the intestine. 

 Along the Oesophagus but attached to the interior sur- 

 face of the proboscis by a sort of mesentery, there is an 

 extremely thin tubular contractile vessel, which takes its 

 beginning from the tentacular circlet and extends right 

 down to the end of the proboscis (it could not be traced 

 further). The organ of generation is attached to the 

 oesophagus and to the circumvolutions of the intestine; 



