THE ORGANS OF CIRCULATION AND RESPIRATION. 



135 



N 



Fig. 73. Heart, Alary Muscles, and Tracheal Arches, seen from below ; to the left 

 is a side view of the heart. T- , T 3 , A ] , alary muscles attached to the second 

 thoracic, third thoracic, and first abdominal terga. X G. Fig. 35 (p. 74) is 

 not quite correct as to the details of the heart. The thoracic portion should be 

 chambered, and additional chambers and alary muscles represented at the end 

 of the abdomen. These omissions are rectified in the present figure. 



