1855.] Remarks on the different species of Orang-utan. 519 



two latter symphises united. Our male Pappan had not quite com- 

 pleted his growth ; for some of the epiphyses are loose, and others 

 are but partially soldered : those of the humeri are fixed and semi- 

 anchylosed ; as are also those of the left radius and ulna ; but the 

 epiphyses of the right radius and ulna are detached ; those of the 

 scapulae and ilia are fixed but slightly, and those of the ischia more 

 extensively. This animal had therefore (as will be attempted to be 

 shown presently) not completed its full growth : the female being 

 much more advanced in age, with its teeth proportionally worn 

 down. On comparison of the skulls of the two sexes, that of the 

 female is seen to be smaller, with the maxillsB less protruded, in- 

 creasing the facial angle from 32° to 35° ; the zygomatic arch is 

 much less robust ; and the longitudinal grinding surface of the 

 upper molars less by T 3 ^- in., while that of the lower molars is less 

 by i in. than in the youthful male presented by Mr. Nicholls, and 

 by ^g- in. than in Dr. Clarke Abel's Sumatran male. In the form 

 of the ascending ramus of the lower jaw, this female specimen 

 more nearly resembles the Sumatran male referred to than any 

 other of our numerous specimens ; but the condyle is considerably 

 larger ; and, as compared with Mr. NicholPs Bornean male, the 

 antero-posterior diameter of the ascending angle is much less; 

 being in the Bornean male (on a level with the surface of the grind- 

 ers) 2f in., — in Abel's Sumatran male but 2\ in., — and in Sir J. 

 Brooke's Bornean female 2|- in. Lastly, this Bornean female pre- 

 sents the very extraordinary anomaly (throughout the series of 

 placental mammalia) of a fourth true molar above and below, though 

 on the left side only : that of the upper jaw being of small size 

 and round form, its crown scarcely exceeding that of an upper 

 false molar of Macactts ehestjs ; and it is placed posteriorly to the 

 ordinary last true molar on a line with its outer surface, that tooth 

 having been pressed a little inward : in the lower jaw the accessory 

 fourth true molar is very little smaller than the normal molars ; 

 and it projects from the internal margin of the anterior surface of 

 the ascending angle of the jaw, its crown being directed obliquely 

 inwards much more than forwards or upwards : as a functional 

 tooth, it must, therefore, have been almost useless ; though the 

 outer or upper margin of its crown is a little worn down by attri- 



