THE SKULL IN GENERAL. 73 



and especially projection forwards of the incisors, so that those of the upper meet 

 those of the lower jaw at an angle, instead of both sets being nearly perpendicular 

 as in cultivated nations. Elongation of the face downwards may be regarded as a 

 specially human characteristic connected with the use of voice and speech, but projec- 

 tion of the jaws forwards is only advantageous for the seizure of food, and gives an 

 appearance of approach to the still further projected form of the jaws in the lower 

 animals, particularly when accompanied, as it often is, by deficient development of 

 the chin. 



The degree of projection of the face in different races of men, and its prominence 

 and increased proportion to the cranium in the lower animals, Camper proposed 

 to express by the angle contained between two lines, one of them descending from 

 the most prominent part of the forehead to the incisor margin of the upper jaw, the 

 other passing through the meatus auditorius externus and the nasal spine : this he 

 termed the facial angle. He estimated its maximum in the European adult at 80, 

 and in the skull of a young negro he found it diminished to 70 ; while in antique 

 works of art he pointed out that it was increased for artistic effect to 90 or more, 

 an extent never realised in nature. In animals, the facial angle is always much 

 lower than in man. According to Camper and Lawrence, it reaches in the young 

 orang as high a point as 56 or 60 ; but in the adult orang they found it attaining 

 only to 47, while Owen finds it to be as low as 30. (Owen, " Zoolog. Trans.," 

 vol. i. p. 373.) Several modifications of Camper's angle have been suggested ; but, 

 like it, they all labour under the disadvantage of being subject to modification from 

 other peculiarities besides the relations proposed to be estimated. 



A convenient method of comparing the skulls of different races was introduced 

 by Blumenbach, and has been much employed, the norma verticalis, or examination 

 of the skull by looking perpendicularly down upon it, which exhibits in one view the 

 proportionate length and breadth of the cranium, the projection of the jaw beyond 

 the forehead, and the lateral prominence of the zygomatic arches. In addition to 

 the norma verticalis and profile view, Prichard has likewise employed the front view 

 in examining skulls, showing that, whereas, in well-formed European heads, lines 

 drawn from the zygomatic arch and touching the temples are parallel, the same lines 

 in the skulls of Esquimaux and others meet over the forehead, and form with the 

 basis a triangular figure. 



More recently, a classification of skulls has been made by Retzius, which has 

 met with considerable acceptance. According to his arrangement, they may be 

 primarily divided into the dolichocephalic, or those which are elongated from before 

 backwards, and the brachycephalic, or those which have nearly as great breadth as 

 they have length. In each of those divisions are distinguished the prognathous skulls, 

 or those in which the upper jaw is visible when they are examined by the norma 

 verticalis, and the orthognathous, in which the jaw is overhung by the forehead. The 

 nations of Western Europe present the orthognathous dolichocephalic type of skull ; the 

 African negro the prognathous dolichocephalic type ; the Slavonic nations exhibit the 

 orthognathous brachycephalic type ; the Mongolians the prognathous brachycephalic. 

 (Camper, " On the Connection between Anatomy, Drawing, &c.," transl. by Cogan, 

 1794 ; Blumenbach, ""Institutions of Physiology," by Elliotson, 1820; and "De Generis 

 Humani Varietate Nativ&,"3rd edition, 1795; Prichard, " Researches into the Physical 

 History of Mankind," and "Natural History of Man; " Morton, " Crania Americana;" 

 Thurnam and Davies, " Crania Britannica ; " Huschke, " Schadel, Him, und Seele 

 des Menschen und der Thiere, &c,," 1854 ; Meigs, " Cranial Characteristics otthe Races 

 of Men," Philad. 1857 ; Retzius, " On the present State of Ethnology with reference 

 to the Form of the Skull," translated in Brit, and For. Medico-Chir. Review, April & 

 July, 1860 ; Carpenter, in " Cyclop, of Anat. and Physiol.") 



IV. Irregularities of Form. The most frequent irregularity in the form of the 

 skull is want of symmetry. This sometimes occurs in a marked degree, and there is 

 probably no skull perfectly symmetrical. The condition which has been observed to 

 co-exist most frequently with irregular forms of skull is synostosis, or premature 

 obliteration of certain of the sutures. The cranial bones increase in size principally 

 at their margins ; and when a suture is prematurely obliterated, the growth of the 

 skull in the direction at right angles to the line of suture may be supposed to be 

 checked, and increased growth in other directions may take place to supply the defect. 



