46 DISTINCTIVE CHARACTERISTICS OF MAN. 



in this position, the face is directed forwards without any effort, owing to the 

 mode in which the head is obliquely articulated with the spine (Fig. 7). 



28. The Cranium of Man is further distinguished from that of the an- 

 thropoid Apes, not merely by its great capacity, but also by its smoothness; 

 its surface being almost entirely deficient in those ridges for the attachment 

 of muscles, which are remarkably strong in both the Chimpanzee and the 

 Oraug, and which impart to its configuration somewhat of a carnivorous 

 aspect. This aspect is strengthened by the great depth of the temporal 

 fossa, and by the extent and strength of the zygomatic arch ; features that 

 are most remarkably developed in the Troglodytes gorilla (Fig. 7). The 

 breadth of the upper part of the face, is a noticeable feature in Man ; the 

 eyes being set widely apart, and the interorbital space occupying one-fourth 

 of the interval between the outer walls of the orbits. 1 The inner walls of 

 the orbits formed by the ossa plana of the ethmoid are nearly parallel to one 

 another. .Moreover, the jaws in even the. most degraded races of Man pro- 

 ject far less from the general plane of the face, than they do in the Apes ; 

 and his teeth are arranged in a continuous series, without any hiatus or any 

 considerable difference in length ; whilst all the Apes, in their adult state 

 at least, are furnished with canine teeth of extraordinary length, between 

 the sockets of which and those of the adjoining teeth (anteriorly in the 

 upper jaw, and posteriorly in the lower) there is a vacant space or " dias- 

 tema." Even in the most prognathous Human skulls, moreover, the in- 

 cisors meet each other much more nearly in the same axis than they do in 

 the anthropoid Apes, in which they form an angle with each other that is 

 not nearly so divei'gent. The fusion of the intermaxillary or premaxillary 

 bones with the superior maxillary, at an early period of foetal life, is a re- 

 markable character of the Human cranium, as distinguishing it from that 

 of the Apes, in which the intermaxillary bones remain separate to a much 

 later period, sometimes differing also very considerably both in size and 

 shape. Thus, in the Troglodytes gorilla, the bones are not only remarkable 

 for their prominence, but also for their upward extension round the nostrils, 

 so that they completely exclude the maxillary bones from their borders, and 

 from the basis of support for the nasal bones ; and although they coalesce 

 with the maxillaries at and near the alveolar portion, they remain separate 

 elsewhere. The lower jaw of Man is remarkable for that prominence at its 

 symphysis which forms the chin ; and although this, also, is least developed 

 in the most prognathous Human crania, yet it is never so deficient as it is 

 in the lower jaw of the Chimpanzee and Orang. It is curious to observe 

 that the skulls of the young of Man and of the anthropoid Apes resemble 

 one another much more than do those of the adults ; each tending to diverge, 

 in its advance towards full development, from a type which seemed almost 

 similar in both (Figs. 4, 5, f>). It is at the time of the second dentition, 

 that the muzzle of the anthropoid Apes acquires its peculiar elongation and 

 consequent projection in front of the forehead (Figs. 5, 4); and the whole 

 cast of the features is altered at the same time, so that it approaches much 

 more to that of the lower Quadrumana than would be supposed from ob- 

 servation of the young animal only. 2 In the Human subject, on the other 

 hand, we see that although in the advance from childhood to adult age, 

 there is a progressive enlargement of the face in proportion to the capacity 



1 Huxley's Anatomy of the Vertebrate Animals, 1871, p. 489. 



2 None but young specimens of the Chimpanzee and Orang-outang have ever been 

 brought alive to this country ; and they have never long survived the period of their 

 second dentition. 



