84 ILLINOIS BIOLOGICAL MONOGRAPHS (84 



EXPLANATION OF PLATE 



Fig. 41. — Transverse section through the anterior part of the nasal organ of Ambly stoma punc- 



tatum 13 mm. long. 

 Fig. 42. — ^Transverse section through the middle region of the nasal organ of the same animal. 

 Fig. 43. — ^Transverse section through the choanal region of Amblysloma punctatum 20 mm. 



long. 

 Fig. 44. — Transverse section through the pons ethmoidalis of Amblysloma punctatum 25 mm. 



long. 

 Fig. 45. — ^Transverse section just anterior to the planimi verticale of Amblysloma punctatum 



55 mm. long. 

 Fig. 46. — ^Transverse section through the planum verticale of same animal. 

 Fig. 47. — ^Transverse section through the planum verticale of Amblysloma punctatum at the 



end of metamorphosis. 

 Fig. 48. — Transverse section through the lamina medialis of same animal. 

 Fig. 49. — ^Transverse section through the external naris of Salamandra maculala 25 mm. long. 

 Fig. 50. — ^Transverse section through the choana of the same animal. 

 Fig. 51. — ^Transverse section through the fenestra ethmoidalis of Salamandra maadata 38 mm. 



long. 

 Fig. 52. — Transverse section through the planum basale of Salamandra maculata at the end of 



metamorphosis. 



