88 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[88 



Fig, 

 Fig, 



Fig. 



Fig, 

 Fig, 

 Fig. 

 Fig. 



Fig. 

 Fig. 

 Fig. 

 Fig. 

 Fig. 

 Fig. 



alp 



anc 



u 



ch 



ct 



e 



en 



eng 



fennb 



fen pr 



fr 



k 



Jo 

 le 

 m 

 n 



HO 



oc 



EXPLANATION OF PLATE 



64. — Transverse section through the planum basale of Neclurus maculatus 30 mm. long. 



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



maculatus 45 mm. long. 



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



glutinosum. 



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



68. — ^Transverse section through the planum basale of the same animal. 



69. — Transverse section through the planum verticale of the older Ampkiuma means larva 



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



long. 



71. — ^Transverse section through the planum basale of the same animal. 



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



73. — ^Transverse section slightly posterior to the above. 



74. — ^Transverse section through planum verticale of Pipa americana. 



75. — Transverse section through the choanal region of Pipa americana, 



76. — ^Transverse section through the external naris of Hyla pickeringii. 



alary process 

 alinasal cartilage 

 columna ethmoidalis 

 choana 



comu trabeculae 

 ethmoid bone 

 external naris 

 external nasal glands 

 fenestra naso-basalis 

 fenestrated process 

 frontal 



intermaxillary gland 

 organ of Jacobson 

 lamina externa 

 maxillary bone 

 nasal bone 

 nasal organ 

 oblique cartilage 



ol olfactory lobe 



on olfactory nerve 



ond dorsal root of olfactory nerve 



onv ventral root of olfactory nerve 



00 optic organ 



P profundus branch of the fifth nerve 



ph planum basale 



pf prefrontal 



pm premaxillary 



pp pterygoid process 



ps parasphenoid 



pt planum tectale 



pv planimi verticale 



s superficialis of the fifth nerve 



spc superior prenasal cartilage 



V vomer 



t 



