In case of incremental methodology, the development process takes place in different modules. This means the development is carried out in different ways and at the final stage everything is merged. While in case of prototype methodology, a prototype of the project is created and then it is showed to the clients for approval. Once it is approved development process starts. Here the requirements keeps on changing and so the design changes too. To know more about the pros and cons of the two development mothodologies simply check out this article.