378 MR. A. H. G. DORAN ON THE MORPHOLOGY 



the other anthropoid apes ; but the processus brevis is quite as well developed as in our 

 species. 



In the Chimpanzee (PI. LVIII. fig. 4) the malleus is much more human than in the 

 Gorilla or Orang-utan, and is as big as most of the numerous mallei removed by me 

 from adult male skulls in the dissecting-room of St. Bartholomew's Hospital. In the 

 shape of its head, which projects markedly forwards, and in the nature of its articular 

 surface, of which the outer segment is much the widest, it approaches T. gorilla more 

 than Homo or Simla ; but in neck and manubrium it is very human, the only differ- 

 ence being that the latter, in this ape, is rather narrower at the base, and more curved 

 than in Man, and its well-developed processus brevis is directed upwards, and hardly 

 outwards. In length the handle does not exceed that of our species — another prominent 

 distinction from the other two apes. 



The body of the incus resembles that of Homo ; the processus brevis is more slender, 

 and ends in a sharp point, with no trace of any depression on it. The processus longus 

 is rather stouter and shorter than in Man ; it forms, with the posterior crus, a right 

 angle. 



The stapes of an adult Chimpanzee is smaller than the smallest specimen of that 

 bone from Homo in the College collection. The crura are almost equally curved ; they 

 are shorter and more slender than in Man, but wider apart at their insertion. They 

 are well grooved towards the aperture, which is very wide. The base resembles that 

 of Homo, though less distinctly reniform, and equally rounded off at both extremities. 



In the Orang-utan (PI. LVIII. fig. 5) the head of the malleus is rather less developed, 

 and less regularly globular than in Man, and does not project conspicuously forwards 

 as in Troglodytes. The whole bone, however, is of about the average size of its human 

 representative. The articular surface is shaped as in Man, but is less extensive ; it is 

 hardly wider at its external or externo-superior extremity than internally. The neck is 

 as narrow as in the last genus, but rather longer ; and it seems as if the sigmoid ridge 

 had become almost effaced in the process of elongation, being hardly perceptible, though 

 so marked in Troglodytes. 



The manubrium is as long and slender as in the Gorilla ; but the processus brevis is 

 very ill developed, though distinctly bent outwards. The extremity of the manubrium 

 is less dilated than even in Homo. 



In the incudes of Simla, in the College collection, removed from a young male Orang, 

 the body is much more developed *, particularly behind, than in Man, though not as 

 wide horizontally. Hyrtl asserts that the body is markedly smaller. The posterior 

 crus is as small and pointed as in Troglodytes ; but the processus longus is short and 

 slender, and more incurved than in Homo ; the crura too are more divergent. 



The stapes has a very slightly developed head, and much more slender crura than in 

 Troglodytes. The anterior is quite straight, the posterior slightly curved. The base 

 is distinctly reniform, and equally rounded at each extremity. 



* Less of the body is taken up by the articular area than in the incus of Homo, as that surface is smaller abso- 

 lutely and proportionally in this ape. 



