To the question of eyes in primitive crustaceans

Based on a review of studies of functional and comparative anatomy of crustacean eyes, a hypothesis is formed on eyes in primitive crustaceans. It is suggested that they were similar to present-day frontal eyes of the malacostracan type. Neuronal architecture suggests that the development to apposition compound eye followed two main routes, one seen in malacostracansand the other in non-malacostracans. Within the two subgroups different and separate lines have been followed to form specialized apposition types and, within the Malacostraca, superposition
eyes as pointed out by Nilsson (Nilsson, D. E. 1989. Facets of vision, pp. 30-73).