Cystic lesions were found in the telencephalic germinal layer of 12 newborn babies. According to their location, the cysts could be divided into three groups: anterior, middle or thalamostriate, and posterior. The histological appearance of all cysts was essentially the same, but in three cases the germinal layer had a peculiar alveolar type of microcystic degeneration. A constant feature was the presence in the cyst wall of small white granulations composed of germinal cells and/or glial tissue. Cystic degeneration of the germinal layer was usually bilateral and sometimes quite extensive. After the involution of the germinal layer, these lesions are likely to persist as subependymal cysts, characterized by their specific location and the presence of glial granulations.