554 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



resistance than these hard wedges to the expansion of the brain; and 

 the middle hicerated foramina are large, through the spreading of the 

 surrounding parts, Avhile the petrous bones remained stationary. In 

 the African blacks the petrous portion and surface of neighboring 

 bones are often on the level and the middle lacerated space is small, 

 while in the Indians, brown, and some 3'ellow races the conditions are 

 mostly between those of the white and black. The whole process of 

 the changing relations and gradual enlargement of the middle perfo- 

 rated space can be studied in whites alone from childhood to adult 

 life. In all the apes and monkeys and in other mammals the middle 

 perforated space is insignificant and the relative elevation of the 

 petrous portions equals or exceeds that in the orangs. 



There are present in a number of the skulls distinct styloids. The 

 detail conditions in this respect are as follows: 



Styloids. 



In nearly all of the specimens is seen a special spinous process, 

 descending Irom the petrous bone, anterior to the carotid aperture, 

 to the basilar process in front of the jugular foramen. In a few cases 

 a similar process rises from the basilar, and where the two join (as, 

 for instance, in No. 14:2183) there is formed a petro-basilar bridge and 

 canal. In three instances (Nos. 142202, 142199, and 142189) there is 

 an incomplete bridge in the usual place, and a second complete one or 

 nearh' so, a little more anteriorly. The part of the bridge projecting 

 from the petrous bone is already- well developed in the youngest skulls 

 of both sexes. 



The anterior condyloid foramen (which in man is usualh' single and 

 transmits the twelfth cranial nerve with a meningeal branch of the 

 ascending pharyngeal arteiT and its accompanying veins) was found 

 in these, as in previoush' reported (Owen) orangs, to be almost gen- 

 erally double: or there is a single large mouth of two canals, both of 

 fair size (though one, the more anterior, is mostly larger). In onl}' 

 three out of the twenty-six skulls were both the foramen and canal 

 single, and in only one of these (No. 142199) they were so bilaterall3\ 

 On the other hand, in four skulls (Nos. 142188, 142181, 142196, and 

 142201) there were on one side, always the left, three separate canals 

 and foramina. 



