34 TTIOMAS TnVTfillT OX 



between the hasi-occipital and the basi-sphenoiil is quite open on the outside of the base, 

 and closing witliin. (I have observed that these surfaces in the human skull join in the 

 same order.) All traces of sutures between the maxillae and premaxillae are lost. 



The upper epiphysis of the humerus and the lower one of the femur are still 

 separate; those at the other end of these bones have joined. The radius and ulna have 

 the lower epiphyses free and the upper ones fused. In the tibia the lower end is still 

 free and the upper has but very recently united by bone. In the fibula both ends are 

 •still free. The scapula has the end of the acromion and the inferior angle free; the 

 posterior border is still rough, but if any distinct epiphysis existed it has been lost. In 

 the innominate bone there is a very faint trace of siiture remaining opposite the 

 acetabulum. The epiphysis over the tuberosity is joined, but its continuation on to the 

 ramus is presumably lost. The crest is unfinished. The plates on the bodies of the 

 vertebrae are in many instances (probably in most) still separable. In the sternum 

 tlie manubrium is, of course, distinct. Cartilage still separates the first piece of the 

 mesosternum from the others which form one bone. The ensiform is wholly cartila- 

 ginous. 



The Skeleton. 



The skull. This, like the rest of the bunes, is large and strongly marked. Greatest 

 length from posterior occipital protuberance to the front of the premaxillae, 19.5 cm. 

 Greatest breadth a little back of ear in the continuation of the occipital curved line, 

 13.1 cm. Cranial capacity 430 cc. The temporal ridges are strong. Their nearest 

 a])proach to each other is 5 cm. in the frontal region ; their greatest separation is 9.5 cm. 

 at their termination. The orbital borders are rather more strongly raised than in most 

 skulls. The interorbital region is concave vertically. The orbital index of the right 

 orbit is 100; that of the left, 88. (Tbe transverse diameter is taken to the posterior 

 border of the lachrymal groove.) Observations on several chimpanzee skulls impugn the 

 statement that the transverse diameter of the orbit always considerably exceeds the 

 heio-ht. The sphenoidal fissure is small; seen from the inside it does not appear much 

 ]arger than the optic foramen. Beddard mentions its large size in T. calmis. Sutton^ 

 states it is large in T. niger. The extremity of the petrous is nearly 1 cm. in advance 

 of the suture between the basi-occipital and sphenoid on the outside of the skull; on the 

 inside the distance between them is more than half as great. The crista galli is rudi- 

 mentary. The fossa above the cribriform plate is very deep ; much deeper than in 

 " Sally," as is shown by the brain. 



'.Juurn. auat. pliysiol., vol. 18. 



