A CONTRIBUTION TO THE STUDY OF THE SCOTTISH SKULL. 



439 



specimens. The foramen csecum, which might be chosen, has been found also to be 

 very variable, and so I have followed the method advocated by Duckworth (54), 

 i.e. to draw the line from the prosphenion to the nasion or middle point of the naso- 

 frontal suture, which, although not without disadvantages owing to the fact that 

 the nasal bones vary much in the degree to which they extend upon the surface of 

 the skull, is usually easily identified as a definite point. 



For the value of the angle so measured there are many figures available for 

 comparison. To get figures exactly comparable with those of Turner, however, 

 where it was possible in the present series of skulls I drew the anterior line according 

 to his directions contained in the " Challenger" Reports, and will give the mean 



Fio. 18. — Impression of median sagittal section of 

 skull 17, series K. 



Maximum length, 1 89 mm. 

 Basi-nasal length, 101 mm. 

 Spheno-ethmoidal angle, 164°. 

 Spheno-niaxillaiy angle, 89°. 

 Foramino-basilar angle, 156°. 



Fig. 19. — Impression of median sagittal section of 

 skull 13, series K. 



Maximum length, 187 mm. 

 Basi-nasal length, 98 mm. 

 Spheno-ethmoidal angle, 142°. 

 Spheno-niaxillary angle, 75°. 

 Foramino-basilar angle, 136°. 



value for this method from a smaller number of skulls in the series. Cleland (15), 

 instead of the spheno-ethmoidal junction, took as the apex of this spheno-ethmoidal 

 angle the mid-point between the two optic foramina, and his results do not exactly 

 correspond to those given above ; but there is only a slight difference, and we may 

 consider the spheno-ethmoidal angle, as obtained above, to be formed by the " middle 

 base " and the " anterior base " of Cleland. 



The spheno-maxillary angle is the angle enclosed between two lines, the basi- 

 occipito-sphenoid axis as described above, and a line drawn from the spheno-ethmoidal 

 junction to the prosthion. This second line in Huxley's (51) original description 

 passed not through the prosthion but through the akanthion, a point less fixed 

 morphologically than the former. The spheno-maxillary angle is the most important 

 angle for measuring the degree of prognathism, and to it I shall refer later. 



The foramino-basilar angle is that enclosed by two lines, one the basi-occipito- 



