r" horb 



A • ^*» ir^I^TJ — ^ r 



"•» ; **? , 4' •?-• -^' J 



Fig. 65 

 Anuran organisers in Urodele hosts. A piece from the dorsal lip of the blastopore 

 of a gastrula of Bombinator pachypus grafted into a young gastrula of Triton 

 taeniatus induces the formation of a secondary embryo, a, b, Two stages of 

 development of an embryo thus obtained, c, Transverse section through b. Capital 

 letters refer to structures of primary embryo, small letters to secondary embryo. 

 Au, optic- vesicle; Ch, notochord; Horb, ear- vesicle; M, neural folds; Md, neural 

 tube; Urw, mesodermal somites; of primary embryo, ch, grafted notochord; 

 horb, ear- vesicle; m, neural folds; md, neural tube formed from graft tissue; 

 md', neural tube induced from host-tissue ; ms, undifferentiated mesoderm of graft 

 tissue ; urw', mesodermal somites induced from host-tissue. (From Geinitz, Arch. 

 Entiumech. cvi, 1925.) 



