Normal Platcs of the Development of Lepidosiren paradoxa and Protopterus annectens. 



17 



Digestive tract 

 and liver 



Pancreas 



Visceral 

 clefts 



Thyroid 



Post- 



branchial 

 l)odies 



Lung 



Urogenital 

 System 



Haart and 

 vessels 



Myotomes 



Splanchno- 

 coele 



Stage 



Gut rudiment solid 



except in neigh- 



bourhood of open 



ings of archineph- 



nc ducts. Anus 



closed. Liver rudi 



ment split off from 



main mass of yolk. 



Postanal gut he- 



Coming reduced 



Liver distinguished 



from main yolk by 



fine grained yolk 



Traversed by rieh 



network of blood 



vessels. (Gut 



lumen only in 



cloacal region.) 



Postanal gut dis' 



appeared. 



Buccal lumen de 

 veloped but not yet 

 open to exterior. 

 Extends back into 

 pharynx but not to 

 glottis. In midgut 



lumen between 

 pylorus and liver, 

 then solid nearly 

 to cloacal region. 

 Small lumen roun- 

 ded in section and 

 varying in thick- 

 ness developed for 

 Short distance in 



front of cloaca. 



Spiral groove 



developed slightly 



at hina end. Shai- 



low dorsal Valley 



along midgut in 

 which the lungs lie 



Solid. 



In form 

 of solid 

 projec- 

 tion of 

 pharyn- 

 geal floor. 



Attachment of pro- 

 nephric glomerulus 

 now medio-dorsal. 



(Mesonephric 



tubule ruaiments 



make their appea- 



rance.) 



Heart a simple 

 curved tube: 

 contractile fi- 



brils in mj'ocar- 

 dium. Dorsal 



aortadilatedbut 

 not yet quite 



circular in sec 

 tion. 



(29+. Six aortic 



arches devel 



oped.) 



(Eye muscles in- 

 dicated by conden- 



sations of mes- 

 enchyme. Agar.) 



Solid. 



Solid, 

 still con 

 nected by 



narrow 

 neckwith 



buccal 

 rudiment 



in front 

 of root of 



tongue- 



(Yolky 

 rudiment 

 on left 

 side pro- 

 jecting 

 forwards 

 from side 

 of pha- 

 ryngeal 

 floor ven 

 tral to 

 aortic 

 arches VI 

 and V.) 



Rudi- 

 ment 

 solid in 

 front : 

 with split 

 like ca- 

 vity be- 



hind : 



bicuspid 



posterior 



ly; left 



pointpro- 



jecting 



farther 



back than 



right. 



Yolky pro 

 jection from 

 dorsal side 

 of gut rudi- 

 ment to left 

 of midline 

 and just be- 

 hindopening 



of foregut 



into midgut. 



Wide cavity 



which opens 



into gut 



lumen. 



No clefts 



perforate. 



Cleft II 



almost 



perforate. 



Yolky 



rudiment 

 on left 



side. Iso- 

 lated 



from Pha- 

 rynx. 

 Blood 

 vessels 

 begin- 

 ning to 



penetrate 



Lumen appearinj 



as split in some 



mesonephric tubule 



rudiments. Most 



still solid. Some 



becoming fused 



with archinephric 



duct at outer end, 



Anterior end of 



archinephric duct 



and pronephric 



tubules much 



distended. 



(31 +, Agar. Pro- 



nephrocoeles open 



to pericardium by 



pericardio-peri- 

 toneal ducts : about 

 26 tubule rudi- 

 ments.) 



Blood red. 



(Mandibular 



and hyoidean 



aortic arches 



reduced.) 



31 +. Posterior 



cardinals be- 

 ginning to fuse 



Lung 

 rudiment 

 well de- 

 veloped 

 withwide 



lumen 

 reaching 

 to glottis 



double 



except at 



its Iront 



end. 



Two pronephro 

 stomes: archi- 

 nephric duct much 

 dilated in front. 

 (Secondary pro- 

 nephric Chamber 

 open behind into 

 splanchnocoele.) 

 Some mesonephric 

 tubules have devel 

 oped a lumen, open 

 into archinephric 

 duct at one end 

 and are slightly 

 dilated at the other 

 to form the rudi- 

 ment of the Mal- 

 pighian body. 



Outer wall be- 

 ginning to thicken 

 and to develop con- 

 tractilefibrils. Inner 



wall myoblasts 

 converted almost 

 entirely into fibrils. 

 Mesenchyme be- 

 ginning to wander 

 in between myo- 

 tomes. 



(Lateral 

 plates not 

 yet met in 



trunk: split 

 in anterior 

 Segments. 



Cavity con- 

 tinued as 

 pericardio- 

 peritoneal 

 ducts into 



pericardium. 

 Agar.) 



Heart still tubu- 

 lär. 

 (Rieh vitelline 

 network cover- 

 ing ventral and 

 lateral a.spects 

 of gut. Drains 

 anteriorly into 

 large irregulär 

 subintestinal 

 vein which 

 passes into liver. 

 Right anterior 

 Cardinal in front 

 much larger 

 than left.) 



(31 + Pro- 31 

 nephric 

 Chamber 

 open to peri- 

 cardium by 

 pericardio- 

 peritoneal 

 ducts. Ven- 

 tral com- 

 munication 



between 

 pericardium 

 and main 

 splanchno- 

 coele in ad- 

 dition to 

 pericardio- 

 peritoneal 

 ducts. 

 Agar.) 



Normentafeln zur Entwicklungsgeschichto der Wirbeltiere. X. 



