I ( 467 ) 



f TABLE XI. 



Systematic Survey showing the derivation of the germ-layers of the Aniphioxu* 

 from the parent-cell (oytula), and of the main organs from the germ .layer*. 



1 



(Tree showing the ontogenetic descent of the cells in the Amphioxus). 1 ** 



Medullary tube 

 Tubus meduUaris 



Sense-organs 



Semuaria 



Outer skin 

 Kpidermie 



s» 



Flesh-mass 

 Musculi 



Notochord 



chorda 



I. 



Blood -vessels 



Canales Gill-epithelium 

 tangueferi Epith. branchiaU 



Leather skin 

 Cerium 



Primitive 



kidneys 



Pro- 

 tonephra 



-• v- 



Testes Ovaries 



Ttiticuli Ovaria 



Parietal 



Coelom- 



Epi- 



thelium 

 Exoca- 

 larium 



Visceral 

 Coelom- 



Epi- 



thelium 



Endocoe- 



larium 



Intestinal 



muscle 



wall 



Peri- 



tn.te.rwm 



Stomach 

 epithelium 



Mesen- 

 tery 



Mesen- 

 terial* 

 I 



Liver 

 epi- 

 thelium 



Small 

 intestine 



epi- 

 thelium 



Epithelium 



digest ivum 



Skin-sensory Skin-fibrous 



layer layer 



Ijimina neurodermalis) {Lamina inodermalW) 



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



Intestinal-fibrous Inte^tinal-glan- 



lay -r dular layer 



{Lamina irwgastralis) (Lamina myxogash 

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



-y- 



Exoderma (Fig. 155, *) 

 flSkiu- layer, or outer germ-layer) 



-y~ 



Ento-'erma (Fig. 155, i- 

 (Intestinal layer, or inner germ-layer) 



Gastrula fFig. 22, j,k ~| 



(Cup-germ) LFig. 155. p. 444 J 



Blastula (Fig. 22, F, 0) 

 (Bladder-germ) 



Mo*ula (Fig. 23, B) 

 (llulberry-germ) 



Cytula (Fig. 22, B) 

 (Parent-cell) 





Monerula (Fig. S2, A) 

 (Farent-cytod) 



(15) 



