NO. l8 ANTHROPOLOGICAL WORK IX PERU IIRDLICKA 59 



reach in regard to this symmetric osteoporosis is that it represents 

 a process not well known in the pathology of the white race, though 

 perhaps not limited to the ancient Americans. 1 



EAR EXOSTOSES : OSTEOMA OF THE TYMPANIC RING 



A relatively large proportion of the pre-Columbian people of the 

 more central parts of the Peruvian coast suffered, as shown by the 

 skulls, from a greater or lesser occlusion of the external auditory 

 canals by bony tumors. These are generally hard osteomata, from 

 one to three in number, ranging in size from those like a minute 

 drop to those of several millimeters in diameter, mostly rounded or 

 pearl-shape, but occasionally irregular, frequently with enamel-like 

 surface, and situated just within, or perhaps protruding slightly from, 

 the orifice of the osseous meatus. These little tumors, which are 

 associated with no signs of any inflammatory nature, develop inva- 

 riably from the tympanic ring and particularly from its extremities. 

 They were in no case seen to coalesce, and though they may almost 

 close the meatus they were never seen to do this entirely. Similar 

 osteomata occur, though far less frequently, among the whites ; they 

 have been mentioned by Virchow from Peru ; and they are found 

 occasionally in the skull of a North American Indian. 



"MUSHROOM-HEAD" FEMUR: ARTHRITIS DEFORMANS OF 

 THE HIP-JOINT 



Never seen in the young, and only once met with in an adolescent. 



Evidently always of gradual development. 



Occurs unilaterally (more frequently) or bilaterally (due to 

 nature of material exact data in this respect not possible). 



Sex influence? 



Never found advanced to synostosis. 



As a rule, without any exception, there were no accompanying 

 changes in the shaft or lower extremity of the same bone, barring 

 an occasional slight to moderate arthritis. 



1 In 1909 the writer brought two infant skulls with a coral-like osteoporotic 

 development in the roof of each orbit from a Xllth dynasty cemetery in 

 Egypt; while Virchow reported (Verh. Berl. Ges. Anthr., 1874, 61-62) similar 

 lesions in a skull of a Pampa Indian from Argentina, and mentions of having 

 seen much the same in the cranium of a young Berliner. It is, of 

 course, possible that such isolated orbital lesions are not homologous patho- 

 genetically with the process described above, but they are of identical character. 



