COMPARATIVE ANATOMY. 



Orang-outang 67 



Long-tailed monkies ... 65 



Baboons 40 to 30 



Pole-cat 31 



Pug-dog- 35 



Mastiff; the line passing along^ 

 the outer surface of the V 41 



skull J 



Ditto ; inner ditto .... 30 

 Leopard ; inner surface . . 28 



Hare 30 



Ram 30 



Horse . . ' 23 



Porpoise 25 



In the third and fourth tables of Cu- 

 vier's " Tableau Elementaire del'Histoire 

 Naturelle," the crania of several mam- 

 malia are represented in profile, so as to 

 afford a sufficient general notion of the 

 varieties in the facial angle. A similar 

 comparative view, in one plate, is given 

 by White, in his account of the "Regu- 

 lar Gradation," &c. from the work of 

 Camper. 



A vertical section of the head, in the 

 longitudinal direction, shews us more com- 

 pletely the relative proportions of the cra- 

 nium and face. In the European, the area 

 of the section of the cranium is four times 

 as large as that of the face ; the lower jaw 

 not being included. The proportion of 

 the face is somewhat larger in the ne- 

 gro : and it increases again in the orang- 

 outang. The area of the cranium is about 

 double that of the face in the monkeys ; 

 in the baboons, and in some of the carni- 

 vorous mammalia, the two parts are 

 nearly equal. The face exceeds the cra- 

 nium in most of the other classes. Among 

 the rodentia, the hare and marmot have 

 it one third larger ; in the porcupine and 

 the ruminantia, the area of the face is 

 about double that of the cranium ; nearly 

 triple in the hippopotamus; and almost 

 four times as large in the horse. In rep- 

 tiles and fishes, the cranium forms a very 

 inconsiderable portion of the section of 

 the head, although it is considerably lar- 

 ger than the brain which it contains. 



The outline of the face, when viewed in 

 such a section as we have just mentioned, 

 forms in the human subject a triangle, the 

 longest side of which is the line of junc- 

 tion between the cranium and face. This 

 extends obliquely, backwards and down- 

 wards, from the root of the nose towards 

 the foramen occipitale. The front of the 

 face, or the anterior line of the triangle, 

 is the shortest of the three. The face is 

 so much elongated, even in the simiae, 



that the line of junction of the cranium 

 and face is the shortest side of the trian- 

 gle, and the anterior one the longest. 

 These proportions become still more con- 

 siderable in other mammalia. 



The upper jaw-bones of other mam- 

 malia do not, as in man, touch each other 

 under the nose, and contain all the upper 

 teeth ; but they are separated by a pecu- 

 liar, single, or double intermaxillary bone, 

 which is in a manner locked between the 

 former, and holds the incisor teeth of 

 such animals as are provided with these 

 teeth. It exists also in the pecora, which 

 have no incisor teeth in the upper jaw ; 

 as well as in such genera as have no in- 

 cisor teeth at all ; viz. the duck-billed ani- 

 mal and the armadillo. It is even found 

 in those mammalia which are wholly des- 

 titute of teeth ; as the ant-eater and the 

 proper whales. It is joined to the neigh- 

 bouring bones by sutures, which run ex- 

 teriorly by the side of the nose and snout, 

 and which pass towards the palate, close x 

 to the foramina incisiva. Its form and 

 magnitude vary surprisingly in several 

 orders and genera of mammalia. It is 

 small in many ferae ; as also in the walrus. 

 In the glires it is remarkably large, on ac- 

 count of the immense size of their incisor 

 teeth. 



In human crania, at least those of the 

 foetus and young children, there is a small 

 transverse slit near the foramen ir.cisi- 

 vum, of which Fallopius gave the follow- 

 ing accurate account in the year 1561 : 

 "I find this division. to be rather a slit 

 than a suture, since it does not separate 

 one bone from the other, nor does it ap- 

 pear exteriorly, nor join two bones, 

 which is the office of sutures." " Obs. 

 Anat." 



" Hence I was much surprised to find 

 Vicq D'Azyr, in 1780, discover in this 

 point an unexpected resemblance be- 

 tween the cranium of the human subject 

 and of quadrupeds." Mem. de 1'Acad. 

 des Sc. 1780. 



In the celebrated dispute of the six- 

 teenth century, whether Galen's osteology 

 was derived from the skeleton of man or 

 the ape, Ingrassias argued for the latter 

 side of the question, from Galen's having 

 ascribed an intermaxillary bone to the 

 human subject. And the same author, in 

 his classical " Commentarii in Galeni L5- 

 brum de Ossibus," Panorm, 1603, fol. par- 

 ticularly points out the parts, " where Ga- 

 len, led astray by the dissection of apes, 

 deviates from the true construction of 

 the human boclv." 



