Fiourforklarino'. 



Pl. VI. 



For samtlige figurei- gjælder folgende betegnelser: 

 Eg = Egestionsanbning, Ing = Iiigestioiisaabning, 



Ekt = Ektoderm. Mes = Mesoderm. 



Ent = Entoderm, 

 End = Endostj-1, 



Ej) = E]iicardium, 



G - Genitalorgan, 

 Kd = Gjællesæk, 



Kl = Kloak, 



Nr = Nerveror. 



Od = Oviduct. 

 P})C = Peribrnnchialcavitet, 

 Per = Pericardium, 

 T=Tarm. 



Fig. 1 — 7. Serie af tversnit gjcnnem on knop af Sta- 



dium II. 



Fig. 8. Mediansnit gjenneai en knop at samme 



stadium. 



Fig. 9. Knop af Stadium III, o, seet fra siden, 



6, seet bagfra. 



Fig. lu. Knop ;if Stadium IV. o, seet bagfra. //, 



seet fra siden. 



Fig. 11 — 17. Serie af tversnit gjenneni en knop af Sta- 

 dium III. 



Fig. 18. Skematiseret fremstilling af fori'este del af 



en feldre knop. 



Fig. 19. 20. Fortykket nerveror af Distaplia. 



Fig. 21. — ,, - Diplosoma. 



Fig. 22. — ,, - Botryllus. 



Fig. 23. — „ - Sarcobotrylloides. 



Fig. 24. — .. - Polycyclus. 



Ex|»liiiiati(>ii i)t tlie fiiiures. 



Pl. VI. 



Tiie following abbreviations are used in all the tigurcs: 



Eg = atrial aperture, 

 eJd = ectoderm, 

 ent = endoderm, 

 end = endostyl, 



i'p = epicardium, 

 g = genital organ, 



kd = branchial sac, 



W = cloaca, 



ing = branchial aperture. 

 vies = mesoderm. 



nr = nerve tulie, 



od = oviduct, 

 l)hc = peribrauciiial cavity. 

 lier = pericardium, 

 t - intestine. 



Figs, 



Fig. 



Fig. 



Fig. 



Figs. 



Fig. 



Figs. 



Fig. 



Fig. 



Fig. 



Fio;. 



I — 7. Sei'ies of transverse sections througli a 



l)ud in Stage II. 



8. Median sectiou through a l)ud in tiie same 

 stage. 



9. Bud in Stage III; «, seen. from the side, 

 /;, seen from beiiind. 



10. Bud in Stage IV; a, seen from behind, 



ti. seen from the side. 



II — 17. Series of transverse sections through a 



bud in Stage III. 

 18. Diagrammatic drawing of tiie anterior part 



of an older bud. 

 19, 20. Thickened nerve tube of Distaplia. 



21. — .. ,. - Diplosoma. 



22. — „ ,, - Botryllus. 



23. — ,. ,. - Sarcol)otrylloides. 



24. — „ ,. - Polvcvclus. 



