Figure 23
From: Invertebrate neurophylogeny: suggested terms and definitions for a neuroanatomical glossary
Ommatidia in Crustacea (A) and Hexapoda (B). Cross sections are indicated by arrows. Both ommatidium types are identical in cell types and cell numbers: two corneageneous cells in Crustacea and two primary pigment cells in Hexapoda, four Semper cells forming a crystalline cone, eight retinula cells forming a closed rhabdom. Abbreviations: cc = crystalline cone; cgc = corneageneous cells; ppc = primary pigment cells; rc = retinula cells; rh = rhabdom; sc = Semper cells; spc = secondary pigment cells. Modified from [87], with permission of Wiley.