158 A SURVEY OF THE LATER EMBRYO OR LARVA 



Presumptive medulla 



Mesencephalon 

 Mesocoel 



-Presumptive cerebellum 



Auditory vesicle 



Spinal ganglia Somites 



Neurocoel 



Laterol line organ ^ 



Cranial nerves 



franiol nerve Vlil 

 \Epiphysis 

 ' Diocoel 



\ ' "Head mesenctiyme 



ndolymphatic duct 



ly VIII VII y, 

 Laterol line nerve ' --•»»«»— 

 Tail Somites ^. 



■■- ' "- ^-jg^ '^ -.^ ." . ..^. .. ; :. -. .. -^. _, r. . * '■.- 



Proneptiric ducts 



Optic cup 

 Auditory vesicle 



Anterior cardinal vein 

 Notoctiord 



Optic cup 

 Cranial nerve V 



Mesenchyn 



Yoii^ Left coBlom Liver diverticulum 



Hypoptiysis 



Hindgul 



•=^-' * '^z'^^^-^*^™..^-'' Pharynx 

 Externolgill Branchial artery 



Tail 

 _■>■■ 



Sinus venosus 

 Liver diverticulum I External gills 



Hindqut ^- y ..j^sa^V" 



Yolk 



Right vitelline vem *** Bulbus arteriosus 



Coelomic spaces ^^^^Swft?^**^ y_Jf^:^^ Visceral arches 

 ' ««r a. .11,... _.» 



Vitelline vein 

 'folj'ij— — — , A Sinus venosus 



Proctodeum -..tS^^^^^^?V< ^■'''^'?a>.__ .Thyroid gland 



Mandibular arch 



Heart 

 Pericordiol cavity 



The 7 mm. frog larva in serial frontal sections. 



