ABSTRACT
When front quarters of migrating slugs of Dictyostelium discoideum are isolated by surgery and induced to fruit immediately they produce fruiting bodies with disproportionately large stalks (Raper, 1940). The data in this communication show that the ‘stalky’ character of fruits derived from front quarters persists even if the cells of the front quarters are disaggregated and hence have to reaggregate before fruiting. The data also demonstrate that fruits derived from rear quarters of slugs have disproportionately large spore heads, and that this effect becomes more pronounced with increasing age of the slugs. These observations support the view that the cells of the front and rear of migrating slugs are to some extent committed to different fates.