RESPIRATORY SYSTEM 



59 



crocodiles and chelonia. The occurrence of this state of 

 affairs is not a character of any one group, but it is found 



Snters into 



Fig. 39. — Bbeast Eeqion of Manucodia. 

 Tr, trachea ; F.M, pectoral muscle ; Fcm, femur. 



sporadically, as it were, in members of quite different groups. 

 The facts have been collected into a general account of the 



