THE HYPOMERE (LATERAL PLATE MESODERM) 245 



Cranial nerve VII 



Posterior choroid plexus 



Endolymphatic duot Honzontdl ^,^^. 



Anterior semi-circular senni-circular >*'^^si,-Rhombocoel 



canal canol 



Anterior semi- 



Gill rakers 

 Aortic arch-' 

 Bulbus arteriosus 



Dorsal aorta -,^ 



Aortic orch 



NIolochord 



Anterior \ 



lymph space \ 



Opercular chambei 



Pericardial cavity 



- '' ,' ijrW.'^ ' "^ y-y-^ Ventricle 



"-•'^Opercular channber 



Posterior choroid plexus 



Auditory capsule 



Internal jugular ^' ji:-^' 



ternol carotid artery 



Auricle 

 Pericardial cavity 



Ventricle 



lymph spoce-tt4- ('i. 



Gill filaments 



Internal gills _ . 



Gill chamber 



Pericardial cavity 



/ Ventricle 

 Ventral mesocardium 



Posterior cordinol vein 



Lung bud-* 



Neurocoel Spinal cord 



IMotochord 



Wolffian duct 

 ^5t,,j^Lung bud 



Spirocle' 



Posterior coelom 



14 15 



Serial transverse sections of the 11 mm. frog larva. 



