( 46/ ) 



TABLE XI. 



Systematic Snrvey showing the derivation of the germ-layers of the Amphioxun 

 from the parent-cell (cytula), and of the main organs from the germ-layers. 



(Tree showing the ontogenetic descent of the cells in the Amphioxus).*" 



Medullary tube 

 Tubus medullaris 



Seuse-orgaus 

 Scnsuaria 



Outer skin 

 Rpidermis 



Flesh -mass 

 Musculi 



Notocbord 

 Chorda 



Blood-vessels 



Canales Gill-epitholium 

 fangueferi Ejpith. branchiate 



Leather skin 

 Corium 



Primitive 

 kidneys 



Pro- 

 tonephra 



^ V-. 



Testes Ovaries 

 Tt&ticuli Ovaria 



Parietal 



Coelom- 



Epi- 

 thelium 

 Exocoe- 

 larium 



Visceral 

 Coelom- 



Epi- 



thelium 



Endocoe- 



larium 



^ v_ 



Intestinal 



muscle 



wall 



Peri- 



enterum 



Mesen- 

 tery 

 Mesen- 

 terium 



Stomach 

 epithelium 



Liver 

 epi- 

 thelium 



Small 

 intestine 



epi- 

 thelium 

 I 



Epithelium 

 digestivum 



_>' ^— 



Skin-sensory Skin-fibrous 



layer layer 



(Lamina neurodermalis) (Jjimina inodermalis) 



(Fig. 157, hs) CFig- 157, hf) 



Intestinal-fibrous Intestinal-glan- 



layer dular layer 



(^Lamina inogastralis) (^Lamina myxogas(raliii\ 

 (Fig. 157, dj) (Fig. 157, dd) 



■^r- 



Exoderma (Fig. 155, «) 

 (SkUl-layer, or outer germ-layer) 



Entoderma (Fig. 155, i) 

 (Intestinal Liyer, or inner germ-layer^ 



Gaatrula TFig. 22. J, K "l 

 (Cup-germ) l_Fig. 155, p. 444 J 



Blastula (Fig. 22, F, G) 

 (Bladder-germ) 



Morula (Fig. 22, E) 

 (Mulberry-germ) 



Cytula (Fig. 22, P) 

 (Parent-cell) 



Monerula (Fig. 22, A) 

 (Parent-cytod) 



