Abstract
The distribution and ultrastructure of mitochondria-rich cells in the inner ears of goldfish (Carassius auratus) and tilapia (Oreochromis niloticus) were examined by light and transmission electron microscopes. The mitochondria-rich cells were found in patches in the ampullae of three semicircular canals, sinus superior, utriculus and sacculus in both species. The cells were also found in the transverse canal in goldfish and the lagena in tilapia. They were absent in the goldfish lagena. The cells were characterized by a large number of mitochondria and an associated network of the smooth endoplasmic reticulum. Fenestrated capillaries were distributed in the connective tissue beneath the patches of the mitochondria-rich cells. The distribution and fine structure of these cells suggested their involvement in the ionic control of endolymph.
