NOTES ON ODONTOMES. 
83 
Nor is nature apparently satisfied with these aberrations 
within or about the dental alveoli, but develops a variety of 
odontoid formations in such organs as the ovaries, testes and es¬ 
pecially at the base of the ear. These ear teeth or ear fistulae 
are of more than passing interest, being practically the exclusive 
heritage of the horse, while their origin and relations are shrouded 
in mystery. The parts composing them are typical dental 
tissues, being especially rich in what appears an extra hard and 
translucent enamel, but how, where or why they form seems un¬ 
determined. 
These odontoid masses are found firmly attached at or near 
the base of the ear, and similar neoplasms having a like relation 
to skeletal bones are not known elsewhere outside the usual al¬ 
veoli. These facts suggest some peculiarities of the so-called 
petrous portion of the temporal bone of the horse. While in 
most mammalia the petrous and squamous portions of the tem¬ 
poral bone become fused, it remains so free in solipeds that even 
in the cranial skeleton of old animals, if the soft tissues are dis¬ 
solved, the ear bone is loose and moveable within its socket. 
Thus the horse has a real distinctive ear bone, a part of no other 
bone, the most moveable of all cranial bones, and set in a de¬ 
pression in the surrounding cranial bones almost as a tooth 
within its alveolus, and having within it an important sensory 
nerve, and the bony tissue attains a hardness approaching dental 
tissue. 
Among the many cases of recorded ear teeth there is a sad 
deficiency in precision as to the relations and attachments of 
the neoplasms to neighboring parts, and the ultimate result of 
attempts at surgical treatment. We do not know the precise 
location or attachments to the neighboring bones, whether the 
tooth-like mass was fused with the bone or fixed in an alveolus 
or calyx, and although deaths are recorded due to fracture of 
the cranial bones in attempts at removal, the recorded recoveries 
are as a rule somewhat vague, being apparently based largely upon 
non-return of the patient, which might follow either recovery or 
an unchanged condition after the first operation. We have ob- 
