86 



ILLINOIS BIOLOGICAL MONOGRAPHS 



186 



EXPLANATION OF PLATE 



Fig. 53. Transverse section through the foramen olfactorius of Diemictylus viridescens 38 mm. 

 long. 



Fig. 54. Transverse section through the anterior part of the nasal organ of the same animal. 



Fig. 55. Transverse section through the foramen olfactorius of the adult Diemictylus virides- 

 cens. 



Fig. 56. Transverse section through the pons ethmoidalis of Triton cristatus 28 mm. long. 



Fig. 57. Transverse section through the planurh basale of Triton cristatus 35 mm. long. 



Fig. 58. Transverse section through the planum basale of Cryptobranchus alleghaniensis five 

 weeks old. 



Fig. 59. Transverse section through the anterior end of the nasal organs of Spelerpes bilinea- 

 tus 15 mm. long. 



Fig. 60. Transverse section just anterior to the planum basale of Spelerpes bilineatus 37 mm. 

 long. 



Fig. 61. Transverse section through the same region of Spelerpes bilineatus 46 mm. long. 



Fig. 62. Transverse section through the choanal region of Plethodon erythronotus adult. 



Fig. 63. Transverse section through the lamina medialis of the same animal. 



ce columna ethmoidalis 



ch choana 



ct cornu trabeculae 



fo foramen olfactorius 



fan foramen orbito-nasalis 



ig intermaxillary gland 



jo organ of Jacobson 



Id lacrimal duct 



le lamina externa 



Im lamina medialis 



m maxillary bone 



n nasal bone 



ng nasal glands 



no nasal organ 



ol olfactory lobe 



on olfactory nerve 



oo optic organ 



p profundus of the fifth nerve 



pb planum basale 



pe pons ethmoidalis 



pm premaxillary bone 



pt planum tectale 



PV planum verticale 



5 superficialis of the fifth nerve 



/ trabecula 



