1. Acrania Anencephaly sequence is the progression from a relatively normal-appearing exposed brain due to an absent cranium (acrania) to an amorphous brain mass (exencephaly) to no recognisable brain tissue (Anencephaly) 1

2. Incorporation of 3H-uridine, 3H-histidine and 3H-glucose into some organs (epidermis, CNS, muscles, spinal cord, notochord, liver, gills, intestine) of Branchiostoma lanceolatum (Acrania) and Brachydanio rerio (Teleostei) was investigated by means of comparative autoradiograms following incorporation periods of 11 min to 7 days.