280 CHARLES B. STOCKAED AND A. L. JOHNSON 



bottom of the figures. The outlines for the long and the round 

 skulls correspond from point to point in fairly symmetrical 

 fashion, and the positions in inclinations of the foramina 

 magna are close together. The solid outline of the achondro- 

 plasic skull not only diverges from the general pattern of 

 the other two, but the outline for the skull base departs 

 completely from that for the normal types. The spindleform 

 outline of the foramen magnum inclines upward and forward 

 instead of being in almost horizontal position. In the bulldog 

 typed skull, the mid-line of the skull base from the anterior 

 border of the foramen magnum curves strongly downward 

 as it passes forward to the base of the vomer, whereas in 

 the normal skulls this line passes from the anterior border 

 of the foramen magnum upward and forward to the base of 

 the vomer. In the bulldog skull there would seem to be a 

 pull toward the occipito-sphenoidal junction in the basi- 

 cranium, bringing the lower frontal and occipital regions 

 toward each other ventrally, and causing the region around 

 the border of the foramen magnum and the basicranium to 

 bend upward and give the strongly arched mid-line shown 

 in the outlines. 



At the right in text-figure 64, the achondroplasic specimen, 

 represented in dotted line, is matched against the solid out- 

 line of the dolichocephalic skull. The contrasting directions 

 of the lines indicating the basicranium, the posterior border 

 of the vomer and the bony palate are more clearly shown in 

 this figure with only the two skull outlines involved. 



After examining the arrangements at the base of the skulls, 

 we are now prepared to interpret the cranial index of the 

 achondroplasic skull as compared with those for the normal. 

 The top views of the three crania (pi. 51) are quite different 

 in outline. The dolichocephalic skull is long anteroposteriorly 

 and narrow transversely, and when viewed from the top its 

 outline forms an elongated oval. This form gives the low 

 cephalic index. As the name indicates, the brachycephalic 

 cranium (fig. 3) is short anteroposteriorly and broad trans- 



