292 PROFESSOR D. J. CUNNINGHAM ON 



The specimens in which it occurred were the following :— 



Macacus cyclops . . . .3 times 



Macacus nemestrinuts 

 Macacus rhesus 

 Macacus speciosus 

 Cercopithecus 

 Cercocebus 

 Cynocephalus niger 



Cynocephalus porcarius . . 1 ,, 



The skull of a young specimen of Macacus cyclops is figured in PL I., fig. 14. It 

 exhibits a somewhat unusual condition, and the supraorbital region in two other skulls 

 belonging to the same species presented a similar appearance. A slightly raised oval 

 field above and behind the glabella and inner part of the supraorbital margin represents 

 the superciliary eminence. It is quite isolated, and stands apart from the glabella 

 and the margo supraorbitalis. 



The skull of an older specimen of macaque monkey (Maxacus rhesus) is seen in 

 PL I., fig. 15. In this specimen the three elements of the eyebrow region are also distinct 

 from each other, but the superciliary projection is very different in form and in its 

 degree of prominence. It forms a pronounced, elongated eminence which runs out- 

 wards above the margin of the orbital opening, and presents a different texture from 

 that of the surrounding bone. Its outer extremity runs into the trigonum supra- 

 orbitale and reaches the anterior part of the temporal ridge, with which it in part fuses. 

 Throughout its whole length it is separated from the margo supraorbitalis by a strongly 

 marked groove, whilst its inner end remains distinct and does not run into the 

 glabella nor fuse with its fellow of the opposite side. 



A somewhat similar arrangement is seen in the skull of an adult specimen of the 

 black ape of the Celebes (Cynocephalus niger). The superciliary eminence is in the form 

 of a sharply marked ridge placed above the margin of the orbital opening, and separated 

 from it by a deep sulcus. Its outer end remains free and ends in the trigonum supra- 

 orbitals In the median line there is a small rounded prominence which lies between 

 the inner ends of the two superciliary ridges, and probably represents the glabella. 



Tn the young chacma baboon (Cynocephalus porcarius) we sometimes meet with a 

 condition which presents a strong resemblance to what is seen in cases where Type I. 

 of this region is present in the human skull (PL I., fig. 17). The strongly marked 

 superciliary eminences are semilunar in outline and curve upwards and outwards from 

 the region of the glabella to the temporal ridge on either side. The eminences remain 

 distinct from each other, but turn downwards into the glabella. A broad, shallow groove 

 separates the superciliary ridge from both the inner and outer parts of the margo 

 supraorbitalis. 



It must be clearly understood that I do not put forward these specimens, all of 

 which fall clearly within the limits of Type I., as being characteristic of the species of 

 ape to which they belong. As in the case of the same form of eyebrow region in the 



