VARIETIES OF MANKIND. 



1299 



of a change of habits, provided such change 

 could be induced. Thus we find that in clogs, 

 the general form of the cranium, and the 

 sagittal crest, undergo considerable modifica- 

 tion ; the brain acquiring a very large size, in 

 several of the domesticated races, at an early 

 period of life ; and the parietal bones being 

 expanded over it so as to form a smooth 

 dome, instead of rising up to meet in a ver- 

 tical ridge. But the prominence of the supra- 

 orbital ridge does not seem to be in any way 

 connected with the relative development of 

 the cerebrum and of the muscular system ; 

 and as Prof. Owen remarks, " We have no 

 grounds from observation or experiment to 

 believe the absence or the presence of a pro- 

 minent supra-orbital ridge to be a modifiable 

 character, or one to be gained or lost through 

 the operation of external causes, inducing 

 particular habits through successive genera- 

 tions of a species. It may be concluded, 

 therefore, that such feeble indication of the 

 supra-orbital ridge, aided by the expansion of 

 the frontal sinuses, as exists in man, is as 

 much a specific peculiarity of the human 

 skull, in the present comparison, as the ex- 

 aggeration or suppression of this ridge is 

 respectively characteristic of the chimpanzees 

 and orangs." The same may be said of nearly 

 all the other distinctive characters which 

 have been so minutely enumerated ; for they 

 serve to distinguish the great chimpanzee 

 from all the varieties of the human race, 

 from the most degraded African, as well as 

 from the most elevated European. The 

 shape, size, and construction of the " pre- 

 maxillary" bones (" inter-maxillaries " of the 

 ordinary nomenclature) are peculiarly distinc- 

 tive ; for they not only differ from those of 

 Man in their vastly greater proportional size, 

 their greater prominence, and the longer per- 

 sistence of their sutures, but also in their 

 upward extension around the nostrils, so that 

 they completely exclude the maxillary bones 

 from their borders, and form the bases of 

 support for the nasal bones (j%. 800.) It 

 is to be remembered that the apparent defi- 

 ciency ofthe inter-maxillary bone in the human 

 subject is the result of its early coalescence 

 with the maxillary ; and that this coalescence 

 maybe prevented by an arrest of development, 

 so that the two bones remain permanently 

 distinct.* 



Having dwelt thus fully on the distinctive 

 features of the Osteology of Man, it will be 

 sufficient to pass over his other peculiarities 

 of conformation more cursorily, referring to 

 the article QUADRUMANA for more minute 

 details. In his Myology, the most charac- 

 teristic difference is the much greater de- 

 velopment of those muscles of the trunk and 

 limbs, which contribute to the maintenance of 

 the erect posture. Thus the gastrocnemii 

 and the other muscles which tend to keep 

 the leg erect upon the foot, form a much 



* A very definite account of the early embryonic 

 state of the intermaxillary bone, is given by Dr. 

 Leidy in the Proceedings of the Academy of the 

 Natural Sciences of Philadelphia for 1848. 



more prominent "calf" than is seen in any 

 other animal. So, again, the extensors of the 

 leg upon the thigh are much more powerful 

 than the flexors ; a character which is pecu- 

 liar to man. The glutasi, by which the pelvis 

 is kept erect upon the thigh, are of far greater 

 size than is elsewhere seen. The superior 

 power of the muscles tending to draw the 

 head and spine backwards, has been already 

 referred to. Among the differences in the 

 attachment of individual muscles, we may no- 

 tice that the flexor longus pollicis pedis pro- 

 ceeds in man to the great toe alone, on which 

 the weight of the body is often supported ; 

 whilst it is attached in the chimpanzee and 

 orang to the three middle toes. The latissi- 

 mus dorsi of man is destitute of that pro- 

 longation attached to the olecranon, which is 

 found in most of the lower Mammalia, and 

 which exists even in the chimpanzee, pro- 

 bably giving assistance in its climbing 

 movements. The larger size of the muscles 

 of the thumb is, as might be expected, a 

 characteristic of the hand of man, though the 

 number of muscles by which that digit is 

 moved is the same in the chimpanzee as in 

 the human subject. The existence of the 

 extensor digiti indicis, as a distinct muscle, 

 however, is peculiar to man. 



The visceral apparatus of Man presents 

 very few characteristic peculiarities, by which 

 it can be distinguished from that of the 

 higher Quadrumana ; among the most re- 

 markable is the absence of the laryngeal 

 pouches, which exist even in the chimpanzee 

 and orang-outan, as dilatations of the laryngeal 

 ventricles. Of the anatomy of the last-named 

 animals in their adult condition, however, we 

 know as yet too little, to enable its resem- 

 blance to that of man to be confidently pro- 

 nounced upon. 



The conformation of the brain -of Man 

 does not differ so much from that of the 

 chimpanzee and orang, as the superiority of 

 his mental endowments might have led us to 

 anticipate. The following are the principal 

 differences which it seems to present: 1. 

 The mass of the entire brain is considerably 

 larger in proportion to that of the body, and 

 in proportion also to the diameter of the 

 nerves which are connected with it. 2. In 

 the external configuration ofthe cerebrum, 

 we notice that the posterior lobes are more 

 developed, so as to project further beyond 

 the cerebellum than they do in any of the 

 quadrumana ; the convolutions are more nu- 

 merous, and the sulci are deeper. 3. On ex- 

 amining the internal structure, it is found 

 that the peripheral layer of grey matter is 

 thicker, the corpus callosum extends further 

 backwards, and the posterior ^ornua of the 

 lateral ventricles are relatively longer and 

 larger than they are in any Quadrumana. 4. 

 The cerebellum, also, is proportionally larger, 

 The great size ofthe cranial portion ofthe 

 skull in Man, as compared with the facial, 

 produces a marked difference between his 

 facial angle, and that of even the highest 

 Quadrumana. According to Camper, who first 

 4o 2 



