Quarterly Journal of Microscopical Science, Vol s3-105, 91-98, Copyright © 1964 by Company of Biologists

The Histochemistry of the Saccus Vasculosus of Notopterus Chitala (Teleostei)

¹ Department of Zoology, University of Delhi, Delhi 6, India

The saccus vasculosus of Notopterus chitala is situated posteriorly to the pituitary gland. It consists of a number of loculi surrounded by blood sinusoids. The loculi open into a number of collecting channels which unite and ultimately drain into the third ventricle of the brain. The loculi are lined by a layer of pear-shaped ‘coronet cells’. The coronet cell has an apical protrusion provided with hairs, each ending in a globule. The coronet cells contain glycogen, especially in the apical protrusions and in the globules. Phospholipid, alkaline phosphatase, and mitochondria are concentrated in the apical protrusion and globules. There are also mitochondria round the nucleus. The Golgi element is not only present in the characteristic Golgi zone but occasionally round the nucleus as well. It has been stated by other authors that acid mucopolysaccharides are synthesized in the coronet cells of the rainbow trout and ‘secreted’ into the lumen of saccus vasculosus. However, acid mucopolysaccharides are not histochemically demonstrable in the coronet cells of Notopterus. The observations recorded in this paper indicate that the coronet cells in the saccus vasculosus of Notopterus are secretory and that glycogen is abundant in them.