( 526 ) 
of this opening, which, however, comes practically to the same 
thing, if a connection between position and slope be assumed. 
‘‘Biegt am Vorderschadel”, he says (l.c. p. 50), “der Oberkiefer 
des Menschen mehr nach vorn (Prognathismus) so rackt zugleich 
am Hinterschadel das Foramen medullare mehr nach riick warts”. 
Aeby 1 ) does not agree with Huxley: “Huxley glaubte die Neigung 
mit dem Prognathismus in Verbindung bringen zu konnen. Die Steil- 
heit der Stellung sollte in gleichem Masse tfie die letztere wachsen. 
In unseren Tabellen findet sich keine Bestatigung dieser Ansieht” 
(l.c. p. 17). Aeby himself sees a connection between the degree of 
development of the occiput and the slope of the Foramen magnum: 
‘Die Abflachung des Hinterhauptes fiihrt eine Erhohung des Foramen 
magnum im Gefolge ” This opinion does not really differ in prin¬ 
ciple from Welcker’s, for if the occiput be markedly flattened the 
Foramen magnum will lie further back, and thus the opinions of 
Welceer and Aeby coincide after all with the opinion already 
expressed by Daubenton, that the For. magn. is the more perpen¬ 
dicular m proportion as it is pushed further backwards. The con¬ 
nection which Huxley believed he had shown was, however of 
another kind, and Aeby is therefore not correct in representing his 
opinion as being in contradiction to Huxley’s. For it is not impos¬ 
sible that the slope is proportional on the one hand to the degree 
of prognathism, and on the other to the position. Is then the relation 
etween position and slope of such a constancy as Topinard made 
it appear originally when he said *) ; "qu’il su ffi t de mesnrer l’un 
des deux termes par exemple l’inclinaison du trou occipital pour 
connaitre 1’autre, c’est a dire la quantite du deplacement du trou”? 
This seems a priori improbable, since Topinard’s method of deter¬ 
mining each of the two phenomena possesses merely a very relative 
degree of accuracy. Indeed Topinard himself saw this later 3 ), and 
then expressed himself more cautiously: “Toutefois il n’y a pas un 
parallelisme rigoureux entre les deux phehomenes ” 
In general the above writers determined the slope of the Foramen 
magnum by determining the angle which was formed between the 
a8e-line adopted by them, and the line which connects basion and 
opisthion. The base-line in these researches connected the basion 
with the nasion or typhlon, and therefore ran through the skull- 
base. This method has been contested by Broca, and quite justly, 
or t e size of the angle which is formed by these two lines is 
i) G. Aeby, Die schadelformcn der Menschen und Affen. Leipzig 1867. 
> F * Topinard. L’Anthropologie. 4me Edition. 
*) P. Topinard. Elements d’AnthropoIogie generate. 
