STAGING OF AMPHIBIAN EMBRYOS 



75 



Foregut 



Reel 

 ProcfOdCun- 



Head mesenchyme 

 Oral evagmotion 



Liver 



1 of the late neuru 

 pipiens. (Redrawn and modified after Huettner.) 



p3rl mesenchyme 

 Liver diverticulum 



Three-dimensional representation of the late neurula stage of the frog, Rana 



Auditory veS'Cle 

 Epimeric mesoderm | Rhombocoel 



Neurocoel 



Mesocoel 



Tuberculum posterius 

 Prosocoei 

 tnfundibutum 



Optic vesicle 



Eorly hypophysis 

 ^S'omodeum 

 Orol evdginotion 



Phorynx 



Heort mesenchyme 



Liver diverticulum 



Three-dimensional representation of the tail bud stage of the frog embryo. 

 Rana pipiens. (Redrawn and modified after Huetlner.) 



Wfsenchyme 



Rhombencephoion 

 Auditory vesicle 

 Posterior cardinal vein 



Caudal vein 

 Caudol arleiy 



Nerve VII 

 Nerve V 



Mesencepholon 

 Epiphysis 



Anterior card 

 inol vein 

 Optic cop 

 Lens 

 OHoctory pit 



Internal carotid 

 artery 



y<^y^'HypophySiS 

 f^-^'i ■" \/oral evoginatlon 



*?^r*''~|-->:5^Pharyn« 

 Atrium \ Sucker 



___^__ ventricle ) Thyroid 



/ Right vitelline vein Sinos venosus Aortic orch 



Pronephric due' 



Reconstruction of the 7 mm. frog larva showing the major organ systems from 

 the right side. (Redrawn and modified after Huettner.) 



Viscefol orches 

 111 IV V 

 \ 



Pronephric tubules 

 Notochord 



\ Mesenchyme 



III IV V 

 Aortic orches 



Frontal (horizontal) reconstruction of the external gill stage of the frog larva. 

 (Redrawn and modified after Huettner.) 



Reproduced from Rugh's - THE FT^OG, 

 McGraw-Hill and Co. , 1960. 



