264 PROCEEDINGS OF THE ACADEMY OF [1888. 



The folds may be contiguous only. In 90 examples I found the 

 arrangement on the right side 3 times, on the left 1, and for both 5. 



It is probable that some forces create the variations above noted, 

 which are distinct from those already named. They are evidently 

 often out of harmony with one another,-the right side exhibiting 

 their effects oftener tliau the left. Sometimes they are operating 

 on the ends of the folds, sometimes in their entire length of the median 

 halves. That they are correlative with morbid phenomena is un- 

 doubted (see p. 269). For the clumping of the rugse their entire 

 length is often found in atrophic foetid catarrh, and in the senile 

 state. Butit may be so by coincidence. No data exists which covers 

 the entire range of appearances. Certainly nothing comparable to 

 such dispositions are seen in the lower animals. 



The term concresence is an exact and convenient term to use in 

 describing this class of modification of the rugifi. 



The common abortion of the first and second post-sutural rugae 

 is not the least instructive of the changes affected by concresence. 



, Figure 7. 



The incisorial pad is divided by a transverse groove. The raphe 

 shows'a tendency to right and left subdivision. The left sutural ruga 

 is deflected backward along the raphe. The post-sutural rugae are 

 irregular. A small pre-sutural ruga is evident. The right post- 

 sutural rugae tend to be oblique, especially in their displaced median 

 ^ elements. Median and lateral concresence is shown on the right side. 

 The deflection of the left sutural fold backward along the raph6 

 is probably also an example of concresence. But for some reason 

 it does not tend to unite with the post-sutural. 



