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TABLE IX. 



Systematic Survey of the most important homologies between the human 

 embryo, the embryo of the Ascidian, and developed Amphioxus on the 

 one hand, and on the other hand, the developed Man. 



Embryo of 

 Ascidian. 



Developed 

 Amphioxus, 



Human 

 Embryo. 



Developed 

 Man. 



I. — Products of the Differentiation of the Skin-layer. 



Naked outer skin 

 Simple medullary 



tube 

 Primitive kidney (?) 

 (excretory canal?) 

 Simple thin leather 



skin (Corium) 



Simple skin-mus 

 cular pouch 



Notochord 

 No skull 

 No limbs 

 Hermaphrodite 

 sexual glands 



Naked outer skin 

 Simple medullary 



tube 

 Primitive kidney (?) 



Simple thin leather 

 skin (Corium) 



Simple trunk- 

 muscle system 



Notochord 

 No skull 

 No limbs 

 Separated sexual 

 glands 



Naked outer skin 

 Simple medullary 



tube 

 Primitive kidney 



duct 

 Simple thin leather 



skin (Corium) 



Simple muscle- 

 plate 



Notochord 

 No skull 

 No limbs 

 Hermaphrodite 

 sexual glands 



Hairy outer skin 

 Brain and spinal 



marrow 

 Oviduct and 



sperm-duct 

 Differentiated 

 thick leather skin 



(Corium) 

 Differentiated 



trunk-muscle 



system 

 Vertebral column 

 Bony skull 

 Two pair of limbs 

 Separated sexual 



glands 



II. — Products of the Differentiation of the Intestinal layers. 



Simple body cavity 



(Cceloma) 

 One-chambered 



heart 

 Dorsal vessel 

 Simple liver pouch 



. (?) . 

 Simple intestinal 



tube with gill- 



openinga 



Simple body cavity 



(Cceloma) 

 Simple tubular 



heart 

 Aorta 

 Simple liver pouch 



Simple intestinal 

 tube with gill- 

 openings 



Simple body cavity 



(Cceloma) 

 One-chambered 



heart 

 Aorta 

 Simple liver pouch 



Simple intestinal 

 tube with gill- 

 openings 



Distinct chest and 

 ventral cavities 



Four, chambered 

 heart 



Aorta 



Large differen- 

 tiated liver 



Differentiated in- 

 testinal tube 

 without gill- 

 openings 



