NO. 149.5. 



OBSERVATIONS OX ORANG SKULLS— HRDLICKA. 



555 



The po.sterior cond\'loid fonimiiia. such as occur somewhat irreou- 

 larly in man and each of wliich transmits a vein from the lateral 

 sinus, are absent in the orangs. There are, near the usual location of 

 these foramina in a number of the skulls ver\' small siuolo orifices, 

 usually less than 1 millimeter in diameter, l)ut these are only the 

 o})eninos of the canals of nutrient vessels. The posterior condvloid 

 fossa, however, and the groove leading from it to the anterior condy- 

 loid depression, are invariably well repi-esented. particulai'ly .so in the 

 male skulls. 



The articular surface of the condyles, often doul)le in man, is single 

 in all these specimens. 



The foramen magnum diti'ers greatly in size and shape, as will best 

 be seen from the following figures: 



Mt'd^nnriinnils of ((miiiieu incu/iiHtn. 



It would be interesting to know the height of the different animals, 

 to see what relation it bears to the size of the cord and foramen. 

 The length of the aperture is often augmented by a broad notch in the 

 posterior l)order, and this affects also the plane of the foramen. No 

 such notch occurs normally in man. The axes of the orbits would 

 pass, if prolonged, through the foramen magnum in all the specimens. 



The point of insertion of the middle odontoid ligament on the center 

 of that part of the basilar process which forms the anterior boundary 

 of the foramen magnum is in most of the skulls ver}^ rough, and in 

 some (Nos. 14^181, 142189, 14216;>, 142185, and 142182) a process pro- 

 jects here into the lumen of the foramen. This process occurs also, 

 though much less frequently, in man, and has sometimes erroneously 

 been descril)ed as the third condyle. 



None of the specimens under examination shows the oval jnedio- 

 basilar (''pharyngeal") fossa, or any tubercles, such as can occasion- 

 ally be found in man. on the anterior border of the foramen magnum; 

 nor is there any trace of a true third condyle. 



The base of the skull ))eing damaged in a number of the specimens, 

 and the calvarium b.eing cut in others, it was possible to make a few 

 observations also on some of the ventral jjarfs of the crania. 



The frontal bone shows in some of the specimens quite marked 

 impressions of the brain convolutions, but in others it is nearlv 



