6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93 



Of the 13 American skulls with exostoses in the Ostmann report, 

 12 are from Peru. The total number of Peruvian crania examined 

 is III, which gives the frequency of 10.8 percent. As to location of 

 the abnormality in the 12 Peruvian skulls, there was some form of 

 bony outgrowth three times on the right side, twice on the left, and 

 seven times bilaterally. In the remaining Indians and the three non- 

 Indian skulls with ear exostoses, the condition was bilateral in all. 



Struck by the frequency of the outgrowths in the American Indians 

 and apparently also in the Polynesians, Ostmann collected all other 

 cases relating to these two groups from previous reports, so that the 

 final number of specimens reached 606 Indians (largely Peruvian), 

 with bony ear growths in 78 (11.5 percent); and 283 "Pacific 

 Islanders" with ear exostoses in 10 (3.5 percent). The American 

 skulls included those of Blake and others mentioned in the present 

 references. Ostmann failed to find records of the abnormality in other 

 races. 



As to location, Ostmann saw the exostoses always at the edges of 

 the tympanic ring, on its posterior as well as the anterior border. In 

 one case, however, he found two little " buttons " originating within 

 the meatus near the ring; the picture of that specimen shows the 

 tympanic ring to be thick and bulging at its edges. 



Ostmann enters into the discussion of exostoses of the ear in rela- 

 tion to skull deformation. Like Blake, he has given close attention 

 to the shape and size of the opening of the auditory canal and believes 

 erroneously " that, on the whole, the form of the lumen of the meatus 

 depends on the form of the skull, and that in general dolichocephalic 

 crania will show a rounder, brachycephalic crania a more oblongly-oval 

 meatus." * Artificial deformation of the skull, he believes, has a de- 

 cided effect on the form of the meatus, and the cause of the tympanic 

 exostoses is largely connected with the deformations of the skull. It 

 seems very probable to Ostmann that the narrowing of the opening of 

 the meatus consequent upon the skull deformation results in an irrita- 

 tion which so disturbs the development of the tympanic ring that, 

 especially when any other tendency toward the formation of exostoses 

 exists, hypertrophies in the ossifying parts will result, leading to 

 exostoses."* " The frequent occurrence of exostoses of the outer ear 



I 



■* " Wir konnen deninach sagen, dass die Form des Gehorgangslumens im 

 Grossen und Gaiizen abhiingig ist von der Schadelform, und dass im Allgemeinen 

 zu dem doli(.hocephalen Schadel der mehr kreisrunde, zu dem brachycephalen 

 Schadel der mehr langlichovale Gehorgang gehort." (P. 273.) 



^ " In diesen kiinstlich verjinderten oder in der Veranderung begriffenen Raum 

 wachst der knocherne Gehorgang hinein, und es will mir als sehr wahrscheinlich 



