INTEGUMENTARY COLOR CHANGES IN THE NEWLY-BORN DOGFISH, MUSTELUS CANIS

Abstract

Mustelus canis is an ovoviviparous dogfish whose young, with a body-length of as much as 33 cm., are born dark in tint. Immediately after birth these young respond to their environment in that they change light or dark, conditions brought on by a concentration or a dispersion of their melanophore plgment. Palc bands can be produced on the fins of newly-born Mustelus by cutting their nerves, as can be done with the adults. A young Mustelus responds to injections of adrenalin by blanching and to pltuitrin by darkening as adults do. A newly-born Mustelus shows no evidence of the primary phase of color change seen in some other fishes and in some amphibians. It appears to omit this phase in its ontogeny and is born with a melanophore system that responds in the same way as this system does in the adults.