ANATOMICAL STRUCTURE OF ANTHROPOID APES. 123 



may also be more favourably compared with those 

 of men. 



We have already mentioned the presence of 

 extensive sinuses and cells in the skulls of anthro- 

 poids, exceeding those of human skulls, and this 

 is apparent in the accompanying illustration of 

 a longitudinal section of the skull of a chim- 

 panzee carrigd through its centre (Fig. 39). The 

 length of this skull between the nasal partition and 

 the most prominent part of the occipital bone is 

 128 mm. ; that of the internal space is 108 mm. 

 10 mm. of this difference is due to the depth of the 



Fig. 39. — Sagittal section through the slcuU of a bam-chimpanzee. 



frontal sinuses, and the rest is owing to the thick- 

 ness of the bony part of the skull. In an aged male 

 gorilla, the first measurement is 153 mm., the second 

 115 mm. In another aged gorilla the measurements 

 were respectively 183 mm. and 117 mm. In a 

 still more aged male orang they were respectively 

 140 mm. and 114 mm. The comparative thinness 

 of the centre of the squamous occipital portion is to 

 be noted in the aged gorilla 'male. In the adult 

 chimpanzee the large cells of the squamous portion 



