October 30, 1903.] 



SCIENCE. 



553 



outgrowtlis due to other factors than brain 

 growth iimst be rigorously excluded. Fur- 

 ther, these details will serve to emphasize 

 the interesting fact that the gorilla's skull 

 is decidedly brachycephalic. This charac- 

 ter is by no means restricted to the gorilla, 

 for it has been clearly proved by Virchow, 

 Schwalbe and others that all the anthro- 

 poid apes are markedly round-headed. 

 Ever since the introduction by the illus- 

 trious Swedish anthropologist Anders Eet- 

 zius of a classification of skulls according 

 to the proportions between their length and 

 breadth, great attention has been paid to 

 this peculiarity in different races of man- 

 kind. It has been generally held that 

 braehycephaly indicates a higher type of 

 skull than doliehocephaly, and that the in- 

 crease in the size of the brain in the higher 

 races has tended to produce a brachy- 

 cephalic skull. When the cranial walls are 

 subject to excessive internal pressure, as in 

 hydrocephalus, the skull tends to become 

 distinctly brachycephalic, as a given ex- 

 tent of wall gives a greater internal cavity 

 in a spherical than in an oval form. In esti- 

 mating the value of this theory as to the 

 evolutionary line upon which the skull has 

 traveled, it is obvious that the brachy- 

 cephalic character of the skulls of all the 

 anthropoid apes is a fact which requires 

 consideration. 



Although an adult male gorilla such as 

 I have selected presents in an extreme de- 

 gree outgrowths from the cranial wall 

 nuisking the true form of the cranial cav- 

 ity, the same condition, though to a less 

 marked extent, is met with in the human 

 subject. Further, it is interesting to note 

 that the length of the skull is more liable 

 to be increased by such growths than the 

 breadth, since they occur especially over 

 the lower part of the forehead and to a 

 less degree at the back of the skull, while 

 the side walls of the cranium in the region 



of its greatest breadth generally remain 

 thin. 



Few, if any, fossils have attracted an 

 equal amount of attention or given rise to 

 such keen controvereies as the Neander- 

 thal and the Trinil skull-caps. Accord- 

 ing to some authorities, both these slaill- 

 caps are undoTibtedly human, while others 

 hold that the Neanderthal belongs to an 

 extinct species of the genus Homo, and 

 the Trinil is the remains of an extinct 

 genxis— Pithecanthropus erectus of Dubois 

 — intermediate between man and the an- 

 thropoids. One of the most obvious and 

 easily recognized peculiarities of these 

 skull-caps is the very marked prominence 

 of the supra-orbital arches. The glabella- 

 occipital length of the Neanderthal is 204 

 mm., and the greatest transverse diameter, 

 which is over the parietal region, is 152 

 mm.— an index of 74.51— while the much 

 smaller Trinil calvaria, with a length of 

 181 mm. and a breadth of 130 mm., has an 

 index of 71.8. Both these skulls are there- 

 fore slightly dolichocephalic. Schwalbe 

 has corrected these figures by making re- 

 ductions in their lengths on account of the 

 frontal 'outworks,' so that he estimates the 

 true length-breadth index of the Neander- 

 thal as 80 and that of the Trinil as 75.5. 

 These indices, thus raised about 5 per cent., 

 are considered to represent approximately 

 the length-breadth index of the cranial 

 cavity. A compari.son of the external and 

 internal mea.surements of many recent 

 skulls with prominent glabellffi would, I 

 .suspect, show a greater difference than that 

 calculated by Schwalbe for the Neanderthal 

 and Trinil specimens. In a male skull, 

 probably an aboriginal Australian, with a 

 cranial capacity of 1227 c.cm. I found that 

 the glabella-occipital length was 189 mm., 

 and the transverse diameter at the parieto- 

 squamous suture 127 mm., which gives an 

 index of 67.20 and makes the skull de- 



