CHAP. IV] THE GENERAL ANATOMY OF GORILLA 



203 



The pleurae have been minutely described by Ruge 1 . As 

 regards their caudal extension along the vertebral column, some 

 approach to the human condition is seen, for the lower limit here 

 is above rather than below the last rib (the latter may however be 

 the thirteenth or fourteenth). Anteriorly (ventrally) Ruge noted 

 a wide interval between the margins of the two pleurae in the 

 sterno-costal region, and in this detail, the Gorilla may be con- 



■srstua&Sn&C 



Fig. 134. An adult male Orang-utan (from a sketch by M. Millot, reproduced 

 with permission from the proprietors of L' Illustration). 



sidered to depart further from the lower Primate type than does 

 Man himself. Laterally the line along which the lower limit of 

 the pleura recedes is closely comparable to its human counterpart. 

 The sub-pericardial sinus (formed by the mediastinal pleura) is 

 retrogressive, though it may co-exist with a small lobus azygos of 

 the right lung. 



1 In the Morphologisches Jahrbuch, Band xix. 



