[The spread of melanoblasts in embryos of different coloured fowls].

The first melanoblasts are found in the embryos of the black Rheinländer and Plymouth Rock chickens at the fifth day of development in the occipital and lumbal region. The further spread of the pigment cells is equal in both races. But at the eight day the pigmented area is much more extended in the Plymouth Rocks. These embryos possess at this time more than twice the amount of melanoblasts which are more pigmented than in Rheinländer embryos of the same age. During the further development this differences are equalized.In both races the colour pattern of the chickens are different and have no similarities with the pattern of adult animals. The different patterns of chickens may be explained by time-dependent, genetic differences during the differentiation of the melanoblasts. The colouration in the adult fowls must be due to different genetic factors, which become effective during the development of the juvenile feathers.