( 467 ) 



TABLE XI. 



Systematic Survey showing tlie derivation of the germ-layers of the Amphioxua 

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



(Tree showing the ontogenetic descent of the cells in the Amphioxus).''^^ 



Medullary tube 

 Tubus medullar is 



Sense-organs 

 Sensuaria 



Outer skin 

 Epidermis 



Flesh-mass 

 Musculi 



Notochord 

 Chorda 



Blood-vessels 



Canales Gill-epithelium 

 savgueferi Epith. branchiate 



Leather skin 

 Corium 



Primitive 

 kidneys 



Prn- 

 tonephra 



-V" 



.^ ^— 



Testes Ovaries 

 Testiculi Ovaria 



Parietal 

 Coelom- 



Epi- 

 thelium 

 Exocce- 

 larium 



Visceral 

 Coelom- 

 • Epi- 

 thelium 

 Endocoe- 

 larium 



Intestinal 



muscle 



wall 



Peri- 



enterum 



Mesen- 

 tery 

 Jllesen- 

 terium 



Stomach 

 epithelium 



Liver 

 epi- 

 thelium 



Small 

 intestine 



epi- 

 thelium 



I 



Epithelium 

 digestivum 



— y- 



Skin-sensory Skin-fibrous 



layer layer 



(Lamina neurodermalis) (^Lamina inodermalis) 



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



Intestinal-fibrous Intestinal-glan- 



layer dular layer 



(^Lamina inogastralis') (^Lamina myxogaxtralia) 

 (Fig. 157, dy) (Fig. 157, dci) 



Exoderma (Fig. 155, e) 

 (Skin-layer, or outer germ-layer) 



■^r- 



._> 



v_ 



Entoderma (Fig. 155, i) 

 (Intestinal Liyer, or inner germ-layer) 



Gastrula ("Fig. 22, j,k n 



(Cup-germ) [_Fig. 155, p. 444 J 



Blastula (Fig. 22, F, G) 

 (Bladder-germ) 



22 



Morula (Fig. 22, E) 

 (M ulber ry-germ) 



Cytula (Fig. 22, B) 

 (Parent-cell) 



Monerula (Fig. 22, A') 

 (Parent-cytod) 



