In Scoliodon the olfactory lobes are olfactory organs
or nasal sacs.
They are present in the olfactory sacs of cranium. They develop from the ectoderm. They open out through the exterior by external nostrils. Each nostril is divided into two parts. In current siphon and excurrent siphon.
The olfactory lobe is lined by olfactory epithelial This epithelium Is called schneiderian membrane. it shows spindle like olfactory cells, sup porting cells and gland cells. The olfactory cells connected with a nerve fiber. All of them are united and olfactory nerve is formed. It will meet the olfactory lobe of the brain. Schneiderian membrane is folded. Hence the olfactory surface is increased.
The folds of two series are set a part by medina raphae. The olfactory cells are sensitive to the chemicals in the water.