20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93 



Meanwhile, as already noted in the first section of this memoir, 

 the material left in San Diego received attention by a number of 

 students from the west coast, two of whom, Burton and Moodie, 

 reported on the ear exostoses of the skulls. Other publications on 

 the growths appeared from time to time. From 1930 to 1932 three 

 especially important studies in this line were published, namely those 

 by Oetteking, Alexander, and Moller-Holst. Moreover, additions 

 were received to our collections which promised to throw additional 

 light on the peculiar disorder. These considerations led me to a de- 

 termination to finish the survey of the subject, add as much as pos- 

 sible to the previous data, and attempt, should the facts warrant, to 

 advance the understanding of the affliction under consideration. The 

 results follow. 



NEW MATERIAL 



The total number of skulls examined for ear exostoses in this 

 new study is 7,814. All these, with the exception of about one-third 

 of the Peruvians, were sexed and examined by me personally. 



The material is part of that of the Division of Physical Anthro- 

 pology, United States National Museum, and the only portion of the 

 specimens reported upon previously were those mentioned casually 

 in my own publications. Only the larger series of our collections were 

 made use of, and such as would give as far as possible a widespread 

 racial as well as geographical and time distribution. 



The abnormal bone formations were found to range without any 

 line of separation from distinct localized " pearls " '" or tumefactions 

 of bone in the external auditory canal to bony tumors that almost 

 fill the distal part of the canal or even protrude outside of it. Only 

 those cases were recorded where the growth presented distinct local- 

 ized welting, excrescence, or tumor. In addition there were fairly 

 numerous cases where a more or less evident trace of a tumefaction 

 or a diffuse pathological thickening of the wall existed ; these were 

 not included in the records. 



The earlier and again the late stages of ear exostoses present diffi- 

 culties to the examiner. The initial tvmiescence, " pearl " or welt, may 

 be ill defined ; and one or two small swellings, welts or " pimples " 

 or ridges, may accompany a larger growth which tends to preempt 

 the attention or obstruct clear vision. Hence no two observers or 

 even repeated examinations by the same student will give absolutely 



" The term " pearl " is particularly fitting, for many of the growths in their 

 earlier stages very closely resemble developing pearls on their mother shell. 



