434 A Studij of the Nam! Bridge in the Anthropoid Apes 
themselves primarily significant for interracial comparison or evolutionary history. 
The intimate correlations of anatomical units renders them also very frequently 
of small importance as hereditary characters, and a complex of anatomical units 
may be much closer to an evolutionary unit, — that entity which as a whole is the 
subject of selective action. For respiratory efficiency the mesodacryal arc may be 
of far more importance than either of its components, the maxillary or nasal bone 
portions. Thus we think it probable that the value of anatomical units in cranio- 
metric measurements is liable to be overrated," and in view of their complex and 
subtle intercorrelations their identification with independent " Mendelian units" — 
whatever the latter may signify — is unjustifiable. 
In the series of cuts on pp. 428 — 9, we have endeavoured to give " type " contours 
of the nasal bridge for various races on the basis of the classification adopted in 
Table XXV. The reader is warned that in any race individuals may be found 
with many of these types. Our "types" are those of individuals whose simotic and 
maxillary nasal angles, and 0, are as near as we could get to the mean values of 
those angles in the race. Not too much weight must of course be placed on the 
classification of races thus reached, but the diagrams are not without suggestive- 
ness. We have added the Dog with its negative simotic subtense, a condition 
which is just readied in one or two Gibbons. In the case of the dog, however, the 
dacryon to dacryon section seems to miss the physiognomic nasal bridge, and we 
have given also a lower section termed on p. 428 the muzzle section. The short 
strokes mark for each contour the limits of the nasal bone; the contours are in 
each case from dacryon to dacryon, and were traced after orientating the skull so 
that the two dacrya and the summit of the bridge were in one horizontal plane. 
Obviously larger numbers of many more races would provide a more adequate 
classification, especially if extended into the animal kingdom generally*. 
* The Gibraltar skull is the only " ancient type " of man for which we have been able to obtain the 
nasal bridge constants. They are : 
Mesodacryal Subtense 8-6, Simotic Subtense 2-8 
Chord 22-0? „ Chord 10-8 
Arc 31-0? 
These give 
a =39-1, a' = U-4, /3 = 40-9, S = 259, 0 = 46°-O, 0' = 27°-5, 
the nasal bridge is thus on the border of the simotic platygephyreal and simotic raesogephyreal groups. 
The difficulty, however, of determining the dacrya in the absence of the sutures in the cast used is very 
Gibraltar Skull. 
considerable. The contour of the nasal bridge is shown above. It will be seen to be in no way 
markedly differentiated. If we accept it as approximating to that of the original, that original would 
have stood somewhere between the Negroes and the natives of the Moluccas for both the maxillary 
and simotic nasal angles, i.e. at the Chimpanzee and Symphalangia end of the scales. But the 
evidence is too fragile to lay any stress on tbis point. 
