2^6 



CHORDATE ANATOMY 



PARIETAL BONE' 

 GYRUS CINGULI 

 PITUITARY, 

 SUBDURAL CAVITY- 

 FRONTAL LOBE 

 FRONTAL BONE- 



yRIGHT CEREBRAL HEMISPHERE 



iRPUS CALU3SUM 



NASAL BONE 

 SPHENOID BONE 

 NASAL CONCHAE 

 EUSTACHIAN TUBE 

 MAXILLA 

 MOUTH CAVITY- 

 PALATINE BONE 

 VESTIBULE 

 SOFT PALATE 

 M. GENIOGLOSSUS 

 MANDIBLE 

 M. GENIOHYOID 



M. MYLOHYOID 



•FORNIX 



PINEAL GLAND 



CORPORA 

 QUADRIGEMINA 



dura mater 

 -occipital bone 

 :erebellum 



ESOPHAGUS' '\:ENTRA 



Fig. 237.- — A median longitudinal section of the human head showing the relations 

 between digestive and respiratory passages in the pharyngeal region. (Redrawn 

 after Braus.) 



MCXTTH INVAGINATION 

 ILL POUCHES 



LUNG 

 SAC 



anlage of lung 



PHARYNX 



pronephros 



Fig. 238. — Stages in the development of lungs in vertebrates. /I is a hori- 

 zontal section of a salamander embryo showing the series of paired pouches which form 

 the gill-slits; after Goette. The last pair of pharyngeal pouches are the anlagen of the 

 lungs. Such evidence suggests that lungs may have arisen in phylogenesis from a pair 

 of gill pouches which failed to reach the surface. B and C are earlier and later stages 

 in the development of the lungs in an amphibian. D is a cross section of the lung anlage 

 in a reptile; after Wiedersheim. (Redrawn from Ihle.) 



