Changes of Colour by Injection of Pituitary Extracts in a Dogfish (Scylliorhinus canicula)

Abstract

INJECTIONS of pituitary extract were performed on an exceptionally light-coloured dogfish obtained in the Aquarium at Dinard in August 1937 ; in this fish the usual large patches were very faint, and, so were the small spots or maculæ. At a distance of ten yards from the tank, the lack of colour of the integument made the animal very easily distinguishable from its fellows. The condition could not properly be described as albinism, the pigment not being altogether lacking: apart from a certain amount of pigment, faintly but evenly extending over the whole of the back, there was a dark spot, about one third of an inch in diameter, behind and above the right gills. With the exception of the pallor of the skin, this male fish was quite similar to the others in size and shape.