what is a pineal gland
The pineal gland, also known as the pineal body, conarium or epiphysis cerebri, is a small endocrine gland in the vertebrate brain.early all vertebrate species possess a pineal gland. The most important exception is the hagfish, which is often thought of as the most primitive extant vertebrate. Even in the hagfish, however, there may be a pineal equivalent structure in the dorsal diencephalon.