Introduction

• The brain is enclosed in a cranium, which is cartilaginous in elasmobranchs and bony in teleost.
• Generally, the brain of fishes is relatively small in comparison to their body size and hence the brain does not occupy the cranial cavity completely, leaving small gap, which is filled with a sort of gelatinous matrix.
• The brain is soft and white and covered by extensive network of blood vessels called choroid plexi.