Fig. 1. Pineal morphology and microanatomy of Sternoptyx diaphana (a–c), Argyropelecus affinis (d–f), Gonostoma elongatum (g) and Chauliodus sloani (h); light micrographs, except c and f (electron micrographs). Abbreviations: bv, blood vessel; Cb, cerebellum; cc, cranial cartilage; ep, pineal neuroepithelium; is, photoreceptor inner segment; l, lumen of pineal vesicle; on, optic nerve; os, outer segment; OT, optic tectum; Pi, pineal gland; st, stalk.