260 PROCEEDINGS OF THE ACADEMY OP [1888. 



II. The rugfe of high Literally compressed as well as the wide, 

 flat vaults are apt to be entire. (See fig. 8.) 



III. The rugre of vaults whose median suture has become the 

 seat of general hyperostosis are always broken. (See. fig. 5.) 



I. Not only is the group of rugae on the left side more prominent 

 than on the right, but the distance from the median line to the 

 canine tooth is greater on the left than on the right side. The 

 pre-sutural space is slightly the more prominent on the left. The 

 left sutural rugse is apt to be inclined backward as it approaches 

 the median line to a point beyond that reached by the right. The 

 right side exhibits a forked sutural ruga, and a larger first post- 

 sutural fold than is seen on the left (see p. 261). The obliquely 

 placed last post-sutural fold is as peculiar to the right side as the de- 

 flected sutural is to the left. 



II. The rugse of the high compressed vaults not only tend to 

 remain unbroken but are well developed. The membranes are 

 thick, cushiony and vascular. The incisors are thrown forward, 

 since they cannot be accommodated in the narrow space between 

 the canines, or the teeth last named remain out of the arch. 



The skeleton is slight and the tonsils large if not hypertrophied. 



The hard palate with a wide, flat arch is associated with thin 

 rugse whose intervals are wide (see figs. 2 and 9). The sutural 

 rugse tend to be deflected less than in the other types. A hyperosto- 

 sis is common. 



III. The form of the wide arch which is modified by the hyper- 

 ostosis of the median structures of the palate is an illustration of 

 the disposition of the bones where they unite one to another by 

 suture to exhibit excess of nutrition.^ 



The raphe is exaggerated, a median bony ridge extends along its 

 line, the pre-sutural region is occupied by thick membranes and 

 prominent neck-folds. The left sutural ruga is apt to incline back- 

 ward at the median line. The right sutural fold is united with the 

 third near the raphe. This group is frequently met with in subjects 

 of nasal catarrh. • 



The rug^ of man as compared with those of the 



lower animals. 

 A generally accepted method of study embraces the variations of 

 human structures and those of the lower animals in which these 

 " variations " are constant. 



1 See a paper by the writer, Am. Journ. of the American Sciences, 1870, 405. 



