A 10-week-old foetus is reported which has various malformations of the spinal cord and vertebrae at the lower thoracic and lumbo-sacral level, as well as a herniation of cerebellar and choroidal tissue down between the bony rim of the foramen magnum and the medulla oblongata. This would constitute, along with another foetus examined, another variant of the malformation ofArnold andChiari.