24 



Normentafeln zur Entwicklungsgeschichte der Wirbeltiere. 



Stage 



Length 



Externa! 

 features 



Chondral 

 skeleton 



Bony 

 skeleton 



Nervous 

 System 



Integu- 

 ment 



Eye 



Otocyst 



Nose 



Hypo- 

 physis 



Pineal 

 body 



Mouth 



XXXII 



Four day 

 larva. 



14 mm. 



XXXIV 



7 day 

 larva. 



16 mm. 



XXXV 



9 day 



larva. 



19 mm. 



XXXVI 



Cloacal 



opening 



lateral. 



Postanal 



region much 



elongated. 



Median fin 



fold ditto. 



First rudi- 



ments of 



limbs visible 



in externa! 



Front part of 



trunk 

 shrinking re- 



latively. 



Limbs now 



project free- 



ly. Oper- 



cular fold 



distinct. 



Anterior 

 part of trunk 



now only 

 slightly bul- 

 ging. Pec- 



tora! linib 

 extends back 

 beyond ex- 

 terna! gills. 



Bulging of 

 anterior part 



of trunk 

 region has 

 disappeared. 

 Cement Or- 

 gan has dis- 

 appeared. 

 Limbs and 

 tail long and 

 slender. 

 Median fin 

 fold very 

 prominent. 



Limb axis 



marked out 



by nuclear 



conden- 



sation. 



Mandibular 



and hyoid 



arch, pec- 



tora! girdle, 



baseof skull, 



auditory cap- 



sule. 



Occipita! 

 arch in con- 

 tact dorsally 



with audi- 

 tory capsule. 



Branchia! 



arches l — 4 



present. 



Neural 



spines con- 



tinuous vyith 



arches. 

 Secondary 

 sheath of 

 notochord 

 not yet in- 

 vaded by 

 cartilage 

 cells. 



Herai- 

 spheres pro- 

 ject for- 

 wards 

 beyond level 

 of anterior 

 end of pri- 

 mary fore 

 brain. 

 Pineal organ 

 developed. 



(Chromato- 



phores 



present on 



dorsal side 



of head.) 



Hind wall of 

 lens vesicle 

 much thicke- 

 ned. Pig- 

 ment present 

 in pigment 

 layer of re- 

 tina. Mes- 

 enchyme in 



optic cup 

 highly 



vascular. 



Canals be- 

 ginning to 

 bulge. Macu- 

 lar thicke- 

 nings ap- 

 pearing. 



(Rods 



developing 



in centre of 



retina.) 



Bony trabe- 

 culae at 



tooth bases 

 spreading 

 along jaws 



and in region 

 of para- 

 splenoid. 



Commen- 



cing in- 



growth of 



lateral 

 plexus into 

 ventricles of 

 hemi- 

 spheres. 



Thin para- 



sphenoid la- 



mella. Palato- 



pterygoid. 



Bone 

 ensheathing 

 hyoid occi- 

 pita! rib and 

 on inner side 

 of 

 Meckel's 

 cartilage. 

 Also on ven- 

 tral face of 

 lower end of 

 pectora! 

 girdle. 



Flask gland 



rudiments. 



Chromato- 



phores. 



Rods 



developed. 



Endo- 



lymphatic 



ducts pass 



dorsalwards 



towards 



midline over 



hind brain 



roof. Out- 



growths 



fore- 



shadowedby 



slight bul- 



gings ? 



Canals for- 



med. 



Endo- 

 lymphatic 

 ducts reach 

 dorsal mid- 

 line and 

 Short out- 

 growths are 

 developed 

 on them. 



Slit-like 

 opening. 



Externa! 



diver- 

 ticulum 

 present. 



Wide 

 lumen. 



(Isolated : 



lying 

 postero- 



dorsal to 

 hyoid 

 arch.) 



Solid. 



Tooth germs 



apparent. 



Lumen devel- 

 oped back 

 into pharynx 

 but not free- 

 ly open to ex- 



terior al- 

 though slight 

 süt present. 

 Lip fold pro- 

 jects down 

 on each side 

 enclosing ex- 

 terna! naris. 

 Lower jaw 

 beginning to 

 grow for- 

 wards. 



Free!}' open. 



