THE ALIMENTARY CANAL AND ITS APPENDAGES 175 



tion, and we have little difficulty in recognising in them the 

 homologues of the " yocal___sacs " of the Monkeys. The latter 

 can be filled with air from the larynx, and in certain Anthropoids 

 they may extend far down in the neck, or even to the shoulder 

 or thorax. These sacs, which, when distended, are really 

 immense, may be partly enclosed in an osseus capsule produced 

 by the transformation of the hyoid (Mycetes). It seems to me 

 that they may not only act as resonators when the animal howls, 

 but that, when inflated, they may serve to intimidate enemies. 



Gruber [and Rudinger] have described cases, in Man, in which the sacs 

 broke through the thyroid membrane and came to lie, like those of the Apes, 

 outside the larynx. [In one case of Rudinger's the sac of the right side 

 was alone present The same variation has been observed by Bischoff in 

 the Gorilla ; and it is interesting to note that inequality in growth of the 

 two sacs has been recorded in the Chimpanzee, the Orang, and in Man. 1 ] 



On examination of the larynxes of a number of Negroes, 

 Giacomini asserts that the ventriculus in no way differs from 

 that of Europeans. [This is, however, in strange contradiction 

 to the conclusions of Gibb, 2 that the larynx of the Negro differs 

 from that of the white races in the invariable presence of the 

 cartilages of Wrisberg, the obliquity of the true vocal cords, and 

 the pendent condition of the ventricles, which latter, according 

 to him, are situated below the plane of the true vocal cords, 

 instead of above it as in the whites.] 



Myologically, Giacomini's inquiry is very interesting. The Italian 

 investigator also examined the Anthropoids, and found that while the 

 Chimpanzee's larynx most nearly resembles that of Man, the Orang's is the 

 least akin to it, and that of Macacus and Cercopithecus occupies an inter- 

 mediate position. 



LUNGS 



Aeby, from a careful study of the structure of the lungs and 



of the arrangement of the pulmonary vessels, has concluded that 



M in Man the upper lobe of the left lung is homologous with the 



I middle lobe of the right, and that the upper lobe of the right 



has no^punterpart on the left side. The question therefore arises 



whether this asymmetry is a primitive condition, or whether the 



left lung may not once have possessed a counterpart to the extra 



lobe now borne by the right, i.e. whether the original plan of 



the tractus respiratorius, as judged by the subdivision of the 



trachea, may not have been strictly symmetrical ? This would 



1 [Cf. Ehlers, Abhandlg. K. Gesellsch. d. Wins. Gdttingen, Bd. xxviii. p. 48.] 

 2 [Mem. Anthropolg. Soc. t Lond., vol. ii. p. 1.] 



