RESPIRATORY SYSTEM 



117 



f e 



upper lobe of the left lung corresponds not with the upper but 

 with the middle lobe of the right lung, Wiedersheim infers that 

 a much more extensive pulmonary respiration and greater 

 activity of the thorax must have 

 existed at an earlier period, later 

 becoming modified through the 

 development of the diaphragm 

 and its coalescence with the peri- 

 cardium l (Primates). From the 

 sinuses of Morgagni, which in 

 reality represent diminished rudi- 

 mentary resonance sacs such as 

 many of the anthropoids possess 

 in a high state of development 

 {see above), Wiedersheim further 

 concludes that the anthropoid 

 progenitors of man breathed on 

 a much larger scale and pos- 

 sessed a far more nowerfnl voral FlG ' 64> Heart, large circulatory trunks 

 6 po werl Ul VOCal an dlungs. (Thome, Zoologie.) a, 



vk ha r k 



Ik 



descending aorta; Ik, left ventricle; 

 rk, right ventricle ; vk, right au- 

 ricle ; ha, vena cava inf. ; 1, trachea ; 

 e and f, two carotid arteries ; dand 

 g, the two venas jug. int., c and 

 i, the two subclavian arteries ; b 

 and m, the two subclavian veins. 



organ than does man at the pre- 

 sent day. 



Some observations in histol- 

 ogy yield the following figures 

 for the dimensions of human (see 

 Fig. 65) and animal bronchioli and alveoli. 

 The breadth of the bronchioli 



in man = O'i8 - O'22 mm. 



the horse = 0-22 - 0*58 



cattle = o'275 



the pig = O'OOS - 0*150 



The average size of the alveoli 



in man = O'2 mm. 



the horse = O'i3 



sheep = o - o6 - OT 

 cattle =0*17 - O'2 

 the pig =0-15-0-2 

 dog = OT i 



1 Wiedersheim, loc. cit., p. 195. 



^M. Sussdorf in Ellenberger, Histologie, pp. 516, 518. 



