On the structure of corpuscular proprioceptive endings in sharks

Abstract

Proprioceptive endings associated with the locomotor musculature are apparently extremely uncommon in fishes. Muscle spindles are absent, and only in elasmobranchs have sensory endings of two types been recognized as proprioceptive. One of these, found in sharks, is the coiled corpuscular ending first observed by Wunderer (1908) at the bases of the fins in various species. This type of ending also occurs sub-cutaneously along the body, superficial to the myocommata (Bone, 1964). Lowenstein (1956) examined the responses of the endings associated with the fin bases, and showed that they were slowly adapting mechanoreceptors, functioning as second order proprioceptors since as the fin was bent, so the connective tissue amongst which the endings lie was stretched or compressed, and the receptor discharged.