Peduncle (anatomy) Peduncle (anatomy) A peduncle is an elongated stalk of tissue. Sessility is the state of not having a peduncle; a sessile mass or structure lacks a stalk. In medicine, a mass such as a cyst or polyp is said to be "pedunculated" if it is supported by a peduncle. There are in total three types of peduncles in the cerebellum of the human brain, known as superior cerebellar peduncle, middle cerebellar peduncle, and inferior cerebellar peduncle. Pedunculated eyes are also the defining attribute of the Stylophthalmine trait found in certain fish larvae. The caudal peduncle is a slightly narrowed part
Operculum (gastropod) pentagram-shaped, and is used to dig into the sand to enable the conch to perform a leaping type of locomotion. The structure of the operculum can be described as follows: In 1998 Checa and Jimeneze proposed three types of opercula: There are two basic types of opercula in terms of their material composition: The different shapes of opercula can include ungulate (hooflike), claw-like, or ovate. The type and shape of the operculum is used to help identify and classify related groups (genera) of land operculates, and likewise some marine operculates. The oldest known human depiction of an operculum together with