88 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[88 



EXPLANATION OF PLATE 



Fig. 64. Transverse section through the planum basale of Necturus maculatus 30 mm. long. 

 Fig. 65. Transverse section through the posterior part of the fenestrated process of Necturus 



maculatus 45 mm. long. 

 Fig. 66. Transverse section through the planum verticale of the younger larva of Epicrium 



glutinosutn. 



Fig. 67. Transverse section through the same region of a 90 mm. Epicrium. 

 Fig. 68. Transverse section through the planum basale of the same animal. 

 Fig. 69. Transverse section through the planum verticale of the older Amphiuma means larva 

 Fig. 70. Transverse section anterior to the planum verticale of Amphiuma means 82 mm. 



long. 



Fig. 71. Transverse section through the planum basale of the same animal. 

 Fig. 72. Transverse section through the anterior planum basale of a larva of Pipa americana. 

 Fig. 73. Transverse section slightly posterior to the above. 

 Fig. 74. Transverse section through planum verticale of Pipa americana. 

 Fig. 75. Transverse section through the choanal region of Pipa americana. 

 Fig. 76. Transverse section through the external naris of Hyla picker ingii. 



al p alary process 



anc almasal cartilage 



ce columna ethmoidalis 



ch choana 



ct cornu trabeculae 



e ethmoid bone 



en external naris 



eng external nasal glands 



fen nb fenestra naso-basalis 



fen pr fenestrated process 



fr frontal 



ig intermaxillary gland 



jo organ of Jacobson 



le lamina externa 



m maxillary bone 



n nasal bone 



no nasal organ 



oc oblique cartilage 



ol olfactory lobe 



on olfactory nerve 



ond dorsal root of olfactory nerve 



onv ventral root of olfactory nerve 



oo optic organ 



p profundus branch of the fifth nerve 



pb planum basale 



pf prefrontal 



pm premaxillary 



pp pterygoid process 



PS parasphenoid 



pt planum tectale 



PV planum verticale 



s superficialis of the fifth nerve 



spc superior prenasal cartilage 



v vomer 



