|Structure et ultrastructure de l'oeil chez les chaetognathes (genres Sagitta et Eukrohnia) = Structure and ultrastructure of chaetognath eyes (genera Sagitta and Eukrohnia)|
Ducret, F. (1975). Structure et ultrastructure de l'oeil chez les chaetognathes (genres Sagitta et Eukrohnia) = Structure and ultrastructure of chaetognath eyes (genera Sagitta and Eukrohnia). Cah. Biol. Mar. 16(3): 287-300
In: Cahiers de Biologie Marine. Station Biologique de Roscoff: Paris. ISSN 0007-9723, more
In this preliminary work in the structure and ultrastructure of Chaetognath eyes it has been demonstrated that: (1) these organisms have 2 types of eyes: cupulian eyes in the gen Sagitta and ommatidian eyes in some spp of the gen Eukrohnia, particularly E. hamata; deep specimens of this later (intertropical zone) show a smaller number of ommtidia than those of the surface specimens from the cold countries: (2) if S. enflata photoreceptors are ciliary type like those of S. scrippsae (Eakin and Westfall, 1964), in 2 spp of serratodentata group, S. tasmanica and S. serratodentata, they seem to belong to the rhabdomeric type; (3) pigment granules migration occurs in the 2 gen and has been watched in E. fowleri and S. setosa whose pigmented area enlarges during the night. The authors have determined by experiments the time of maintenance in the dark necessary to start the migration.