TA BLE OF I'll N T E N TS. 



\ 11 



Inspiration described ....•••■ 



Expiration described .....••• 



Pause .....-•••• 



Absence of analogy between Batrachian and Chelonian respiration 



Obvious objection to the view usually entertained 



Previous experiments of one of the authors 



Direct observation of the inspiratory muscles during life . 



Galvanization of .... • • 



Function of, tested by their removal ... 



Expiratory mnscle . ..... 



I Hrect observation of 



Function of, tested by other means ...... 



Third period of respiratory movement 



Partial expiration ..... • ■ 



Simplicity of plan of respiration in Chelonians 



Glottic muscles ... ... 



Function of ........ 



Opening and closing muscles .... 



Movement of hyoid arches . . ■ • • 



Necessity for firm closure of glottis ..... 



Curious instinctive provision for holding air in the lung .... 



Physiology of pneumogastric nerve and its branches 



General remarks ..... • • 



Experiments on laryngeal nerves 



Superior laryngeal nerve distributed to both glottic muscles 



Inferior laryngeal to the opening muscle only 



Their distribution explains the phenomena observed 



The superior laryngeal the nerve of sensation to the larynx and glottis . 



Hypoglossal nerve . . . 



Supplies the tongue only 



Experiments ....•••• 



Result of experiments, discovery of a true chiasm of the superior laryngeal nerves 



Xo interlateral communication between the recurrent laryngeal nerves 



Experiments proving this ..... 



Discussion as to the reasons for this singular distribution of nerves 



Glottic function in turtles of great importance to their life 



Hence integrity of, guarded with great care 



All the nerves but one may be destroyed, and the glottis continue to act 



Importance of the chiasm in this connection 



Arrangements for protecting the neural apparatus of the glottis 



No chiasm in birds or mammals ..... 



Still to be looked for in Batrachian s, and Ophidian and Saurian reptiles 



Section of pneumogastric nerves in turtles 



Sensibility of pneumogastric . . 



Its relation to cardiac movements 



Spinal respiratory nerves ..... 



Respiratory centre ...... 



Rhythmic repetition of habitual movements in the inspiratory muscles after section of t 



Continuance of glottic movements after section of cervical spine . 



< 'nuse of ...... 



Final conclusions ...... 



Appendix. Respiratory muscles in Trionychida 



e spine 



p An r 

 25 

 2."i 

 25 

 25 

 25 

 26 

 20 

 2G 

 2G 

 2(i 

 26 

 27 



•>7 



28 

 28 

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 20 

 3d 

 3D 

 3D 

 30 

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 35 



.■;."> 

 35 

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 3.-. 

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41 



