Histological Studies on the Pineal Organ of 15 Species of Teleosts∗

Abstract

Histological observations were made on the pineal organ of 15 species of teleosts and the following results were obtained. 1. The presence of pineal window was ascertained in 8 species of fishes. 2. Histologically, piscine pineal organs were classified into 6 types, i.e. flat, fold, convoluted, small space, compact and intermediate types. 3. The presence of cytoplasmic processes into the pineal lumen was confirmed in the pineal epithelium of flat, fold, convoluted and intermediate types. 4. Ganglion cells were detected in the pineal organ of 9 species of fishes, even though they were not typical ones. With reference to the photosensory function, discussion was made on the histological structures of the pineal organ of fishes. © 1969, The Japanese Society of Fisheries Science. All rights reserved.