Development of the otolith in embryonic fishes with special reference to the toadfish, Opsanus tau

The development of the saccular otolith and the otolithic membrane was studied in the toadfish (Opsanus tau) using scanning and transmission electron microscopy. Development of the saccular otolith and its otolithic membrane in Opsanus begins with the formation of the primordia in embryos of 17-20 somite age. Calcification of the primordia begins shortly afterwards, although increased calcium layering and formation of the otolithic membrane corresponds to the development of a group of cells lying peripheral to the developing sensory epithelium. These cells contain an abundance of rough endoplasmic reticulum.