Figure 8
From: Invertebrate neurophylogeny: suggested terms and definitions for a neuroanatomical glossary
Inverse and everse invertebrate eyes. Large arrows indicate direction of incoming light, small arrows indicate orientation of light-sensitive processes of receptor cells. Some receptor cells are labelled blue and some supportive cells are labelled green. A. Pigment cup eye with inverse design of retina in a triclad flatworm, Schmidtea mediterranea. Dendritic processes of photoreceptor cells enter the eye cup through the opening of the pigment cup; the latter exclusively formed by pigmented supportive cells. Somata of photoreceptor cells lie in front of the opening of the eye cup. [TEM micrograph. Manually labelled.] B. Pigment cup eye with vitreous body or lens and everse design of retina in a polychaete, Gyptis propinqua, Phyllodocida. Dendritic processes of photoreceptor cells pass through the pigment cell layer. Note shading pigment within the dendritic processes. [TEM micrograph. Manually labelled.] Abbreviations: br = brain; cu = cuticle; dp = dendritic processes of photoreceptor cell; ecm = extracellular matrix; mu = muscle fibre; pc = pigment cell; rhm = rhabdomeric microvilli; rso = soma of receptor cell; vb = vitreous body. Originals: A: C. Kock; B: G. Purschke.