MUSCLES OF CERATODUS 



347 



so that in u 30 mm. embryo— the latest embryonic stage 

 investigated — the larynx is not covered by the muscle. 



Text-figs. 21-4. 

 Embryo 20 mm., transverse sections ; Text-fig. 21 is the most anterior. 



(xisophi 





'^^^^^^0''^ Trojzs. vent: 



Text-fig. 22. 



cesopK. 



Jrcuhs. veal. V 



Corcsb.oesoplv. 

 larynx Const. Laryru^. 



Greil represents the Transversus ventralis v. in his figure 

 of a model of a 17-8 mm. embryo (Taf. Ixiv, fig. 3) with a 

 markedly convex posterior edge. But I have not found this 

 in embryos of 14, 15, 16, 17-5, 20, 24, 28, and 30 mm. It is 

 concave from the first and remains so during the extension 



