196 EVOLUTION AND DISEASE. 
him that they were always in this fish ; he therefore 
concluded them to be natural to it. 
Bones of this kind are not uncommon in osteological 
collections. Cuvier explains this by stating that they 
are brought home as curiosities by travellers who have 
eaten these fish. No one has attempted to explain these 
curious bones, which are very characteristic ; at one end 
they present a tumour about the size of a chestnut, very 
hard, smooth, and as dense as ivory. Articulating with 
the tumour by means of a shackle-joint, is one, often 
two, small rays. On section the outline of the ray can 
be clearly defined running through the midst of the 
tumour (fig. 105). The fish on which Bell’s original 
description was founded is preserved in the museum of 
the Royal College of Surgeons, and a drawing of the 
specimen is given in “ The Transactions of the Patho- 
logical Society of London,” vol. xxxix. 
A consideration of the bones of the Chetodon is of 
interest in connection with what are known as the horned 
men of Africa. In 1883 Professor Macalister com- 
municated to the Royal Irish Academy a photograph 
of one of these men, who came from Akim on the west 
coast of Africa (6° N,. latitude and 1° E. longitude). 
From an examination of the photograph, as well as 
from the descriptions of those who had examined the 
man, the so-called horns appear to be outgrowths from 
the malar bone and nasal process of the upper jaw. 
This is by no means an infrequent situation for exostoses 
in Europeans, and, as a rule, such outgrowths are sym- 
metrical, and give a very hideous appearance to the 
individual so unfortunate as to possess them. Such 
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