92 



of that animal in the possession of Mr. Cross, Mr. Owen regarded 

 as being that of a male individual from its size and from the deve- 

 lopment of the cranial ridges. 



The sexual pecuUarities obser\'able in the cranium of both the 

 Bomean and Sumatran Pongos are well marked, and are exemplified, 

 first in a difference of relative size, that of the female being about 

 ^th smaller ; secondl}^ in a much smaller development of the cranial 

 ridges ; and thirdly, in the symphysis menti being of less depth, the 

 cranium of the female approaching in these respects, according to 

 the usual law of sexual development, towards the characters of the 

 immature animal. The smaller of the crania of the two Bomean 

 Orangs, Mr. Owen regarded as indicative of a species of Simia, Erxl., 

 equally distinct from the great Pongo of Borneo (Simia JVurmbii, 

 Fischer, Synopsis Mammalium, p. 32, No. 43), and from the Orang 

 of Sumatra (Simia Abelii, Fischer, ibid. p. 10, No. 2*); and whilst 

 regretting that his conclusion as to the specific distinction of the 

 smaller Oraiig, (which, aeter is paribus, must be at least one third less 

 than either of the two preceding Orangs) necessarily reposed on a 

 comparison of the cranium alone, he at the same time observed that, 

 as the cranium in question was in every respect entire, and with 

 the series of teeth complete, it served to establish that deduction on 

 the sound basis of dental and osteological characters. 



Mr. Owen therefore proposed to designate the lesser Orang of 

 Borneo, Simia Morio, and proceeded to describe the cranium as fol- 

 lows : 



"The size and form of the cranium of the Simla Morio at first 

 suggests the idea of its being an intermediate stage of growth be- 

 tween the young and adult Simia Satyrus, or Pongo ; but this is dis- 

 proved by comparison of the teeth of S. Morio, with the permanent 

 teeth in the adult Pongo, and with the deciduous ones in the 

 young Simia Satyrus, as well as with the germs of the permanent 

 teeth concealed in the jaws of the latter. For while the teeth of 

 S. Morio are much larger than the deciduous teeth of the young 

 S. Satyrus, they have different relative sizes one to another from those 

 ■which are observed in the permanent teeth of the full-grown: the 

 molares and bicuspides of the S. Morio being smaller, the canini much 

 smaller, while the upper incisores have nearly, and the lower in- 

 cisores fully, the same dimensions as those of the great Pongo. 



" The teeth in the jaws of a quadrumanous cranium may be known 

 to belong to the permanent series, by the absence of the/orfl/«m«, 

 which, in an immature cranium, are situated behind the deciduous 

 teeth, and which lead to the cavities containing the crowns of the 

 permanent teeth. This character is very conspicuous on comparing 

 the cranium of Simia Morio with that of a young Simia Satyrus, in 

 which the deciduous series are present, together with the first per- 

 manent molares. The deciduous teeth in the young Orang, besides 

 their smaller size, are more or less protruded from their sockets, and 

 thrust apart from one another by the vis a tergo of their huge suc- 

 cessors, while the teeth of S. Morio are lodged firmly in the jaws ; 

 and, with the exception of the characteristic interval between the 



